Systems for distributing data over a computer network and methods for arranging nodes for distribution of data over a computer network

ABSTRACT

Various embodiments of the present invention relate to a system for distributing data (e.g., content data) over a computer network and a method of arranging receiver nodes in a computer network such that the capacity of a server is effectively increased (e.g., the capacity of a server may be effectively multiplied many times over; the capacity of the server may be effectively increased exponentially). In one embodiment the present invention may take advantage of the excess capacity many receiver nodes possess, and may use such receiver nodes as repeaters. The distribution system may include node(s) having database(s) which indicate ancestor(s) and/or descendant(s) of the node so that reconfiguration of the distribution network may be accomplished without burdening the system&#39;s primary server. An embodiment of the present invention may include a process for configuring a computer information distribution network having a primary server node and user nodes docked in a cascaded relationship, and reconfiguring the network in the event that a user node departs from the network. In one example (which example is intended to be illustrative and not restrictive), the process may include the steps of providing a new user node (or connection requesting user node) with a connection address list of nodes within the network, having the new user node (or connection requesting user node) go to (or attempt to go to) the node at the top of the connection address list, determine whether that node is still part of the distribution network, and connect thereto if it is, and if it is not, to go to (or attempt to go to) the next node on the connection address list. In another example (which example is intended to be illustrative and not restrictive), when a user node departs from the distribution network, a propagation signal may be transmitted to the nodes below it in the network, causing them to move up in the network in a predetermined order. In another example (which example is intended to be illustrative and not restrictive), the present invention may provide a decentralized approach which provides, to each new user node (or connection requesting user node) a path back to the root server.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 11/179,063, filed Jul. 11, 2005, which is acontinuation-in-part of U.S. Pat. No. 7,035,933, issued Apr. 25, 2006,and claims the benefit of the filing date of co-pending and commonlyassigned provisional patent application “System for Distributing ContentData Over a Computer Network and Methods for Arranging Nodes forDistribution of Data Over a Computer Network”, Ser. No. 60/586,876,filed Jul. 9, 2004, the entire disclosures of which are incorporatedherein by reference in their entirety.

FIELD OF THE INVENTION

Various embodiments of the present invention relate to systems fordistributing data (e.g., content data) over a computer network andmethods of arranging nodes for distribution of data (e.g., content data)over a computer network. In one example (which example is intended to beillustrative and not restrictive), the systems and methods of thepresent invention may be applied to the distribution of streamingaudiovisual data over the Internet.

For the purposes of the present application the term “node” (e.g., asused in the phrase a first node communicates with a second node) isintended to refer to a computer system (or sometimes just “computer”)configured to send and/or receive data over a computer network (e.g., acomputer network including the Internet, a local-area-network, awide-area-network, a wireless network). Since a “node” in a computernetwork would not exist but for a computer system being available onsuch node, the terms “node” and “computer system” (or sometimes just“computer”) may be used interchangeably (i.e., the term “node” should beunderstood to include an available computer system (or sometime just“computer”).

Further, for the purposes of the present application the term “upstream”(e.g., as used in the phrase a first computer system sends data via anupstream connection to a second computer system) is intended to refer tothe communication path between a first computer system and the Internetwhen the first computer system is sending data to a second computersystem via the Internet.

Further still, for the purposes of the present application the term“downstream” (e.g., as used in the phrase a first computer systemreceives data via a downstream connection from a second computer system)is intended to refer to the communication path between a first computersystem and the Internet when the first computer system is receiving datafrom a second computer system via the Internet.

Further still, for the purposes of the present application the term“uptree” (e.g., as used in the phrase a first node sends data via anuptree connection to a second node) is intended to refer to the networktopology communication path between a first node and a second node whena first node is sending data to a second node which is higher up on thenetwork topology tree (that is, closer to the root server).

Further still, for the purposes of the present application the term“downtree” (e.g., as used in the phrase a first node sends data via adowntree connection to a second node) is intended to refer to thenetwork topology communication path between a first node and a secondnode when a first node is sending data to a second node which is lowerdown on the network topology tree (that is, closer to the leaves).

Further still, for the purposes of the present application the term“docked” (e.g., as used in the phrase a child node docks with a parentnode) is intended to refer to forming a connection between nodes viawhich data may flow in at least one direction (e.g., at least uptree ordowntree).

Further still, for the purposes of the present application the term“apparent available capacity” (e.g., as used in the phrase apparentavailable capacity to transmit content data) is intended to refer to anominal capacity (e.g., a node's presumed capacity based upon a designspecification but not necessarily actually tested in the network).

BACKGROUND OF THE INVENTION

In a computer network such as the Internet, each node in the network hasan address. A computer system resident at a particular address may havesufficient bandwidth or capacity to receive data from, and to transmitdata to, many other computer systems at other addresses. An example ofsuch a computer system is a server, many commercial versions of whichcan simultaneously exchange data with thousands of other computersystems.

A computer system at another location may have only sufficient bandwidthto effectively exchange data with only one other computer system. Anexample of such a system is an end user's personal computer connected tothe Internet by a very low speed dialup modem. However, even typicalpersonal computers connected to the Internet by higher speed dialupmodems may have sufficient bandwidth that they may exchange dataessentially simultaneously in an effective manner with several othercomputer systems. Moreover, an end user's personal computer system mayhave even greater bandwidth when connected to the Internet by ISDNlines, DSL (e.g., ADSL) lines, cable modems, T1 lines or even highercapacity links. As discussed more fully below, various embodiments ofthe present invention may take advantage of the availability of suchhigher capacity end user systems (e.g., those computer systems capableof essentially simultaneously exchanging data with multiple computersystems).

In a typical situation, as shown in FIG. 1, a content providerdistributes its data by making the data available on a server node 8simultaneously to a plurality of users at user nodes 12 (of note, theterms “server”, “root server” and “primary server” may be usedinterchangeably throughout the present application to refer to the samedevice (i.e., the highest level parent node in a given network). Thedouble-headed arrows show the two-way communication between each enduser's computer system and the server. Essentially the contentprovider's server transmits a separate stream of signals to eachreceiver node. To accommodate additional users, the content providerwould typically either add equipment to increase capacity or it wouldengage a mirror site to accomplish essentially the same result as addingequipment. The capacities of the end user computers is of virtually noconsequence in such a system.

Another system for distributing data is the Napster™ music file exchangesystem provided by Napster, Inc. of Redwood City, Calif. A schematic ofthe Napster™ music file exchange system (as its operation is presentlyunderstood) is illustrated in FIG. 2.

More particularly, it is believed that in the Napster™ system a copy ofthe music data is not kept on the server. The server 9 instead maintainsa database relating to the various music files on the computers of userswho are logged onto the server 9. When a first user 12 a sees that adesired music file is available from a second logged on user 12 b, thefirst user causes his computer to query the server 9 for the seconduser's node address and a connection is made between the first andsecond user's computers through which the first user's computer notifiesthe second user's computer of the desired file and the second user'scomputer responds by transmitting a copy of the desired music filedirectly to the first user's computer. It is further believed that afirst user attempting to download a particular file from a second usermust start completely over again if the second user cancels itstransmission or goes off line during the data transfer.

In another area, engineers have developed what is known as “streamingmedia.” In summary, streaming media is a series of packets (e.g., ofcompressed data), each packet representing moving images and/or audio.

To help understand streaming media in more detail, it is helpful toreview the traditional Internet distribution method. Each node (whetherit is a server node or a user node) in a computer network has a uniqueidentification (sometimes referred to as an “IP” address) associatedwith it. On the Internet, the unique address may be referred to as aUniform Resource Locator (“URL”). A user desiring to obtain data from aparticular server enters that server's URL into the user's browserprogram. The browser program causes a connection request signal to besent over the Internet to the server. If the server has the capacity toaccept the connection, the connection is made between the server and theuser node (files requested by the user are typically transmitted by theserver in full to the user node and the browser program may store thefiles in buffer memory and display the content on the user's computersystem monitor—some files may be more permanently stored in the computersystem's memory for later viewing or playing.) The connection with theserver is typically terminated once the files have been received at theuser node (or the connection may be terminated a short time thereafter).Either way, the connection is usually of a very short time duration.

With streaming media, the contact between the server and user nodes isessentially continuous. When a connection between a server node and usernode is made and streaming media is requested, the server sendsstreaming media packets of data to the user node. A streaming mediaplayer installed on the user's computer system (e.g., software, such asRealMedia™ from RealNetworks, Inc. of Seattle, Wash.,) causes the datato be stored in buffer memory. The player decompresses the data andbegins playing the moving images and/or audio represented by thestreaming media data on the user's computer system. As the data from apacket is played, the buffer containing that packet is emptied andbecomes available to receive a new packet of data. As a result, thememory assets of a user's computer are not overly taxed. Continuousaction content, such as, for example, the display of recorded motionpicture films, videos or television shows may be distributed and playedin essentially “real time,” and live events, such as, for example,concerts, football games, court trials, and political debates may betransmitted and viewed essentially “live” (with only the brief delaysneeded for compression of the data being made available on the server,transmission from the server to the user node, and decompression andplay on the user's computer system preventing a user from seeing theevent at the exact same moment in time as a person actually at theevent). And, when the systems are working as designed, the server nodeand user node may stay connected to each other until all the packets ofdata representing the content have been transmitted.

SUMMARY OF THE INVENTION

Various embodiments of the present invention relate to a system fordistributing data (e.g., content data) over a computer network and amethod of arranging receiver nodes in a computer network such that thecapacity of a server is effectively increased (e.g., the capacity of aserver may be effectively multiplied many times over; the capacity ofthe server may be effectively increased exponentially). In oneembodiment the present invention may take advantage of the excesscapacity many receiver nodes possess, and may use such receiver nodes asrepeaters. The distribution system may include node(s) havingdatabase(s) which indicate ancestor(s) and/or descendant(s) of the nodeso that reconfiguration of the distribution network may be accomplishedwithout burdening the system's primary server. An embodiment of thepresent invention may include a process for configuring a computerinformation distribution network having a primary server node and usernodes docked (i.e., connected) in a cascaded relationship, andreconfiguring the network in the event that a user node departs from thenetwork. In one example (which example is intended to be illustrativeand not restrictive), the process may include the steps of providing anew user node (or connection requesting user node) with a connectionaddress list of nodes within the network, having the new user node (orconnection requesting user node) go to (or attempt to go to) the node atthe top of the connection address list, determine whether that node isstill part of the distribution network, and connect thereto if it is,and if it is not, to go to (or attempt to go to) the next node on theconnection address list. In another example (which example is intendedto be illustrative and not restrictive), when a user node departs fromthe distribution network, a propagation signal may be transmitted to thenodes below it in the network, causing them to move up in the network ina predetermined order. In another example (which example is intended tobe illustrative and not restrictive), the present invention may providea decentralized approach which provides, to each new user node (orconnection requesting user node) a path back to the root server.

Of note, various embodiments of the present invention may be applied tothe transmission (e.g., the “appointment” transmission) of audiovisualcontent such as, for example (which example is intended to beillustrative and not restrictive), live or pre-recorded concerts,football games, court trials, political debates, motion picture films,videos or television shows. Such transmission of audiovisual content maybe made with acceptable levels of quality, wherein “acceptable levels ofquality” may vary depending upon the end users and the type oftransmission. Further, such transmission of audiovisual content may becarried out using streaming media transmissions intended to reach largeaudiences, in much the way that television shows transmitted overtelevision cable and broadcast media reach large audiences (in thisregard, the present invention may enable a server to transmit streamingmedia to the large number of users which would be essentiallysimultaneously logging on to view a particular audiovisual presentationunder this television-type “large audience” transmission).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing of a prior art computer informationdistribution network;

FIG. 2 is a schematic drawing of another prior art computer informationdistribution network;

FIG. 3 is a schematic drawing of an embodiment of a computer informationdistribution network formed pursuant to the present invention;

FIG. 4 is a schematic drawing of another embodiment of a computerinformation distribution network formed pursuant to the presentinvention;

FIG. 5 is a schematic drawing of another embodiment of a computerinformation distribution network formed pursuant to the presentinvention;

FIG. 6 is a schematic drawing of a particular topology of a computerinformation distribution network formed pursuant to an embodiment of thepresent invention;

FIG. 7 is a schematic drawing of a particular topology of the computerinformation distribution network formed pursuant to an embodiment of thepresent invention as shown in FIG. 6 (after the occurrence of an event);

FIG. 8 is a schematic drawing of another topology of a computerinformation distribution network formed pursuant to an embodiment of thepresent invention;

FIG. 9 is a schematic drawing of the topology of the computerinformation distribution network formed pursuant to an embodiment of thepresent invention as shown in FIG. 8 (after the occurrence of an event);

FIG. 10 is a flow diagram of an embodiment of the present inventionshowing a Server Connection Routine which may be performed when aprospective child node seeks to join the distribution network;

FIG. 11 is a flow diagram of an embodiment of the present inventionshowing a Prospective Child Node's Request to Server for a ConnectionRoutine;

FIGS. 12A-12E are schematic drawings showing varying topologies of thecomputer information distribution network formed pursuant to anembodiment of the present invention under several circumstances;

FIG. 13 is a block diagram of an embodiment of the present inventionshowing the memory blocks into which the software used may partition auser node's memory;

FIG. 14 is a flow diagram of an embodiment of the present inventionshowing a Prospective Child Node's Connection Routine—the routine whicha new user node (or connection requesting user node) may go through inattempting to connect to a distribution chain (or tree) after receivinga connection address list;

FIG. 15 is a flow diagram of an embodiment of the present inventionshowing a Prospective Child Node's Connection Routine With Return toServer Subroutine;

FIG. 16 is a flow diagram of an embodiment of the present inventionillustrating a Prospective Parent Node's Connection Routine;

FIG. 17 is a flow diagram of an embodiment of the present inventionillustrating a Server's Connection Instruction Routine;

FIG. 18 is a flow diagram of an embodiment of the present inventionillustrating a Fully Occupied Parent's Connection Instruction Routine;

FIG. 19 is a flow diagram of an embodiment of the present inventionillustrating a Multi-Node Selection Subroutine;

FIGS. 20A and 20B are together a flow diagram of an embodiment of thepresent invention illustrating a Universal Connection Address Routine;

FIG. 21 is a schematic drawing of a topology of a computer informationdistribution network of an embodiment of the present invention before anew node will be added using the Universal Connection Address Routine;

FIG. 22 is a schematic drawing of a topology of the computer informationdistribution network of an embodiment of the present invention when anew node is added using the Universal Connection Address Routine;

FIG. 23 is a schematic drawing of a topology of a computer informationdistribution network of an embodiment of the present invention before areconfiguration event;

FIG. 24 is a schematic drawing of a topology of a computer informationdistribution network of an embodiment of the present invention shown inFIG. 23 after a reconfiguration event;

FIG. 25 is a schematic drawing of a topology of a computer informationdistribution network of an embodiment of the present invention, slightlydifferent from the topology shown in FIG. 23, before a reconfigurationevent;

FIG. 26 is a schematic drawing of a topology of a computer informationdistribution network of an embodiment of the present invention shown inFIG. 25 after a reconfiguration event;

FIG. 27 is a flow diagram of an embodiment of the present inventionshowing a Child Node's Propagation Routine;

FIG. 28 is a schematic drawing of another topology of a computerinformation distribution network of an embodiment of the presentinvention before a reconfiguration event;

FIG. 29 is a schematic drawing of a topology of a computer informationdistribution network of an embodiment of the present invention shown inFIG. 28 after a reconfiguration event;

FIG. 30 is a schematic drawing of another topology of a computerinformation distribution network of an embodiment of the presentinvention before a “complaint” regarding communications;

FIG. 31 is a flow diagram of an embodiment of the present inventionshowing a Grandparent's Complaint Response Routine.

FIG. 32 shows one “Virtual Tree” (or “VTree”) embodiment of the presentinvention (in which a server of a distribution network is configured toinclude a number of “virtual” nodes);

FIG. 33 shows another “Virtual Tree” (or “VTree”) embodiment of thepresent invention (in which a server of a distribution network isconfigured to include a number of “virtual” nodes); and

FIGS. 34A-34C relate to various distribution network topology examplesaccording to the present invention.

Among those benefits and improvements that have been disclosed, otherobjects and advantages of this invention will become apparent from thefollowing description taken in conjunction with the accompanyingfigures. The figures constitute a part of this specification and includeillustrative embodiments of the present invention and illustrate variousobjects and features thereof (of note, the same reference numeral may beused to identify identical elements throughout the figures).

DETAILED DESCRIPTION OF THE INVENTION

Detailed embodiments of the present invention are disclosed herein;however, it is to be understood that the disclosed embodiments aremerely illustrative of the invention that may be embodied in variousforms. In addition, each of the examples given in connection with thevarious embodiments of the invention are intended to be illustrative,and not restrictive. Further, the figures are not necessarily to scale,some features may be exaggerated to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

Referring now to FIG. 3, an illustration of a linear propagationarrangement 10 of a computer network according to an embodiment of thepresent invention is shown. In this embodiment, the primary server node(or simply, server) 11 provides content data (e.g., streaming media) touser nodes 12 connected directly to it (sometimes referred to as “firstlevel user nodes”). Each first level user node 12 has a second leveluser node 13 connected to it and each second level user node 13 has athird level user node 14 connected to it. The computer system at eachfirst level user node 12 passes a copy of the content data received fromserver node 11 to the computer system at the second level user node 13attached to such first level user node 12. The computer system at eachsecond level user node 13 in turn passes the content data onto thecomputer system at the fourth level user node 14 attached to it.

As more fully discussed below, under this embodiment the computersystems at the server and user nodes may have distribution softwareinstalled in them which enables the nodes to be arranged as shown andfor the computer systems to receive and re-transmit data.

The cascadingly connected arrangement of nodes (i.e., first level nodesare connected to the server, second level nodes are connected to firstlevel nodes, third level nodes are connected to second level nodes andso on) shown in FIG. 3 takes advantage of the bandwidth available incertain nodes to essentially simultaneously receive and transmit data.In a linear propagation arrangement, the effective distribution capacityof a server is in essence multiplied by the number of levels of nodeslinked together. In the example of FIG. 3 (which example is intended tobe illustrative and not restrictive), the distribution capacity of theserver node is increased from 8 user nodes to 24 in just three levels.

Of note, many user nodes may have at least sufficient bandwidth (e.g.,upstream bandwidth as well as downstream bandwidth) to receive data fromone node and to re-transmit streams of data essentially simultaneouslyto two or more other nodes. This capacity could be used in anotherembodiment to set up a computer network with a cascadingly connectedexponential propagation arrangement 16 (as shown in FIG. 4). As the nameimplies, an exponential propagation arrangement effectively increasesthe distribution capacity of a server exponentially. For example (whichexample is intended to be illustrative and not restrictive), with justthree levels of user nodes, each having the capacity to retransmit twodata streams, the distribution capacity of the server in FIG. 4 isincreased from 8 user nodes to 56.

In another embodiment a distribution network may also be set up as acascadingly connected hybrid linear/exponential arrangement 18, such asshown in FIG. 5.

Of note, the effective distribution capacity grows more quickly in ahybrid linear/exponential arrangement with each new level than does thedistribution capacity in a linear propagation arrangement, and lessquickly than does the distribution capacity in a pure exponentialarrangement. However, any of these arrangements allows a server'sdistribution capacity to be greatly increased (e.g., with little or noadditional investment in equipment for the server). Further, any otherdesired hybrid arrangement may be used.

Referring again to FIGS. 1-5, all of the connections between nodes areillustrated with arrows on each end. This is intended to signify thatdata flows in both directions between connected nodes. For example(which example is intended to be illustrative and not restrictive), auser node connected to a server may transmit data to the serverindicating the identity of the user node, what the user node wantsand/or other data, while the server node may transmits data confirmingits identity and containing information and other content to the usernode. In the remaining drawings such arrows may not be shown for thesake of simplicity. Further, it is noted that the bulk of data which istransmitted may be content (e.g., web pages, music files, streamingmedia), and such content will be understood to flow downtree from nodeto node in the drawings (i.e., in the direction from the root server toa first level node, to a second level node, to a third level node,etc.).

As can be understood from the above, an exponential propagationarrangement may create the most distribution capacity. However, whilemany (and perhaps even most) user nodes may have sufficient bandwidth tore-transmit acceptable quality multiple copies of the data, a number ofuser nodes may not have sufficient bandwidth to re-transmit more thanone copy of the data with acceptable quality, and some user nodes maynot have sufficient bandwidth to re-transmit even a single acceptablecopy. Under these conditions, a distribution system employing thepresent invention may be configured, for example, as a hybridpropagation network. In such a system, a personal computer acting as aserver node may reach many (e.g., hundreds, thousands or more) usernodes, even if the server node itself has capacity to transmit contentdata directly to only one other node.

In the following discussion it will be assumed that the system employingthe present invention will take advantage of the capability of many usernodes to simultaneously re-transmit up to two copies of data (e.g.,content data). However, it should be understood that the invention couldtake advantage of user nodes capable of simultaneous re-transmission ofeven higher numbers of copies.

In one embodiment the length of the distribution chains (i.e., thenumber of levels of user nodes linked through each other to the server)may be kept as small as possible to reduce the probability that thenodes at the ends of the chains will suffer a discontinuity of service.Thus, under this embodiment, in order to maximize the number of usernodes which may be connected to the server while trying to keep thelength of the distribution chains as small as possible, the user nodeshaving the greatest bandwidth may be placed as far up uptree as possible(i.e., be placed as close as possible to the server, where “close”refers to network node level and not necessarily to geographicalproximity).

In this regard, if an unreliable user node is placed near or at the endof a chain, few or no other user nodes would be affected by theunreliable user node's leaving the network. In contrast, if anunreliable user node were placed at or near the beginning of a chain(i.e., be far uptree), many other nodes would be affected by theunreliable node's departure. Because various embodiments of theinvention may be used for appointment viewing of streaming media, inwhich an essentially continuous connection to an audiovisual contentsource may essentially be a necessity, it may be important (e.g., forthis steaming media use) that the most reliable user nodes be placedhigh up in the chain (i.e., high uptree).

A user node may be deemed unreliable for any of a number of reasons. Oneexample (which example is intended to be illustrative and notrestrictive), is that the user node is connected to the Internet bylines having intermittent failures. Another example (which example isintended to be illustrative and not restrictive), is that the user ismerely sampling the content available on the network and intentionallydisconnects the user node from the distribution network after discerningthat he or she has no interest in the content.

Thus, under an embodiment of the present invention the user nodes may bepositioned in the most advantageous positions, taking into account thedynamic nature of the distribution network, in which many user nodes mayenter and leave the distribution network throughout the server'stransmission of a streaming media show. In addition, the invention mayhelp to preserve the viewing experience of users at user nodespositioned even at the end of a distribution chain (the server and/oruser nodes may be enabled to perform the operations required to set upand maintain the distribution network by having data distributionsoftware installed therein).

Referring now to a “User Node Arrival” example (which example isintended to be illustrative and not restrictive), it can be seen fromFIGS. 3-5 that the distribution chains can be viewed as a plurality offamily trees, each family tree being rooted to the server 11 through oneof the first level nodes 12 (each node in the distribution network mayhave distribution software loaded in it which enables the node toperform the functions described below; before any new node may join thedistribution network, such new node may also have such software loadedin it).

Of note, in the bulk of the examples discussed below, the networktopologies have a branch factor of two (i.e., no user node is assignedmore than two child nodes to be connected directly to it). A networktopology with a branch factor of two may be referred to as a binary treetopology. It should be understood, of course, that the teachings setforth herein may be extended to network topologies having other branchfactors, for example (which example is intended to be illustrative andnot restrictive), branch factors of three, four or more.

In any case, FIG. 6 is a schematic drawing of a distribution networktopology useful for describing the current “User Node Arrival” example.This FIG. 6 shows a distribution chain or family tree rooted to theserver 11 through user node A, a first level user node 12 (the dashedlines represent connections from the server to other first level nodesor from node A to another user node). User node A could be thought of asa child node of the server and as a parent node for other user nodesconnected directly to it. User node B, a second level user node 13,could be thought of as A's child. User nodes C and D, third level usernodes 14, may be thought of as B's children and A's grandchildren (andeach other's siblings). User nodes E and F, fourth level user nodes 15,may be thought of as C's children (and each other's siblings). User nodeG, also a fourth level user node 15, may be thought of as D's child. Anduser nodes E, F and G may be thought of as B's grandchildren and A'sgreat grandchildren.

In the present example, whenever a new user node (or connectionrequesting user node) 19, such as node X in FIG. 6, seeks connection tothe distribution network, it will first make a temporary connection tothe server node (or a connection server, not shown) in order to beginthe process for connecting to the distribution system. The server (orconnection server) will discern from the user node a bandwidth rating(discussed below) appropriate to that node and, depending upon theavailable capacity of the server and any existing distribution chains,the server will either assign the new user node to a spot directlyconnected to the server or will provide the new user node with aconnection path through a tree to the server.

FIG. 10 is a flow diagram associated with this example showing aServer's Connection Routine which is performed when a prospective childnode seeks to join the distribution network. In step 101 the serverperforms the Server's Connection Instruction Routine (discussed below),in which the server determines what connection instructions to give tothe new user node (or connection requesting user node). The server thengoes to step 102 where it determines whether, as a result of theServer's Connection Instruction Routine, the prospective child node isbeing instructed to dock with the server. If the prospective child nodeis being instructed to dock with the server, then the server goes tostep 103 in which the server would allow the new user node to dock withit, and the server would begin transmitting data (e.g., streaming media)directly to the new user node.

Of note, as referred to above, two different servers could be used—oneto perform the server's connection routine and the other to transmitdata (e.g., streaming media)—since both servers would be performingserver functions, they will hereinafter sometimes be considered a singleserver for purposes of the description herein.

Of further note, while the prospective child node may be a new user nodeor a connection requesting user node, to simplify the followingdiscussion such prospective child node may simply be referred to as a “anew user node”.

In any case, if the new user node is not being instructed to dockdirectly with the server, then the server goes to step 104 in which itprovides the new user node with an address connection list anddisconnects the new user node from the server.

Essentially contemporaneously with the performance by the server of theServer's Connection Routine, the new user node is performing theProspective Child Node's Request to Server for a Connection Routine.FIG. 11 is a flow diagram associated with this example illustrating theProspective Child Node's Request to Server for a Connection Routine.Upon making the temporary connection to the server, the new user nodegoes to step 111 in which it provides bandwidth rating and performancerating information to the server. It then proceeds to step 112 in whichit receives connection instructions from the server. Then the new usernode proceeds to step 113 to determine whether it has been instructed todock directly with the server. If the answer is “yes,” then the new usernode proceeds to step 114 in which it erases any information which mayhave been in its ancestor database and, if the distribution software hasa Return to Server Subroutine in it, resets the connection attemptcounter to zero. The new user node then proceeds to step 115 in which itdocks with the server and begins receiving data (e.g., streaming media).If the new user node is not being instructed to dock directly with theserver, then the new user node goes to step 116 in which it receives thenew connection address list from the server and loads such list into theuser node's ancestor database and begins the Prospective Child Node'sConnection Routine (discussed below). If the distribution software has aReturn to Server Subroutine in it, the connection attempt counter isreset to one in step 116.

In the examples discussed in connection with FIGS. 6-9 and 12A-12C(which examples are intended to be illustrative and not restrictive),the server has determined that the new user node X will not be allowedto connect directly to the server. Also, for the purposes of theseexamples, all of the user nodes are presumed to be equally capable ofsimultaneously re-transmitting two copies of the content data and thatthe tree rooted through node A is the most appropriate tree throughwhich node X should be connected to the server. In one embodiment theserver may rely on chain length in determining to which particular usernode, already in the distribution network, that node X should connect.

Referring again to the example of FIG. 6, the topology of thedistribution network based on the most recent information available tothe server at the moment that node X seeks to join the distributionnetwork is shown. Path D-B-A-S (where “S” is the server) represents theshortest available path from an end of a chain back to the server (e.g.,from a node level point of view and not necessarily from a geographicalproximity point of view), and the server 11 gives that path information,or connection address list, to node X during step 104 of FIG. 10 (andnode X receives such list during step 116 of FIG. 11). That is, node Xwill be given a connection address list with the URLs and/or IPaddresses of each of nodes D, B, A and S. The distribution software innode X causes the path information to be stored in the ancestor portion(or ancestor database) 132 of node X's topology database 131 shown inFIG. 13. The ancestor database may include an ancestor list, a list ofnode X's ancestors' addresses from node X's parent back to the servernode. (FIG. 13 shows an example block diagram (which example is intendedto be illustrative and not restrictive) showing the memory blocks intowhich the software used in connection with the present invention maypartition a user node's memory 130.) Node X then attempts to contactnode D first, the user node most distant from server 11 in the path.Note that when the server provides the D-B-A-S connection address tonode X, the server is giving what it “believes” to be the complete pathinformation going all the way back to the server. That is, subsequent tothe most recent generation of the topological data, node D may havedeparted from the network, as may have one or more of its ancestors,resulting in a reconfiguration (discussed below) of at least a portionof the tree of which D was a part.

Referring now to FIG. 14 is a flow diagram associated with this exampleshowing the Prospective Child Node's Connection Routine, the routinewhich a new user node, here node X, will go through in attempting toconnect to a distribution chain (or tree) after receiving a connectionaddress list (which node X has stored in the ancestor portion of itstopology database) from the server or from a prospective parent node orduring a reconfiguration event. In step 141, node X attempts to contactthe first node on the connection address list. The first node, and onlynode, on the connection address list could be the server itself Herenode D is the first node on the list. Node X then proceeds to step 142and determines whether the first node on the connection address list isstill on-line and still part of the distribution network (in oneexample, if no response is received within a predetermined period oftime, from the first node on the connection address list, the answer tothe query in step 142 will be deemed to be no). If node D is on-line andstill part of the distribution network, node X proceeds to step 143 inwhich node X inquires whether node D has room for node X. This inquirymay need to be made because the distribution network may have gonethrough a reconfiguration event resulting in node D's not havingsufficient capacity to provide a copy of the content data to node X. Ifnode D has room for node X, then node X proceeds to step 144 in which itconnects (or docks) with node D and begins receiving content data fromit. This is depicted in FIG. 7. Note that node X is now one of severallevel four nodes 15.

On the other hand, in step 142, if node D is not on-line (e.g., noresponse is received from node D within a predetermined period of time)or if node D is on-line but is no longer part of the distribution system(e.g., subsequent to the server's obtaining its topology data the userof the system at node D either caused his or her computer system to gooff-line or to leave the distribution system, or there was a linefailure causing the computer system to go off line), as depicted in FIG.8, then node X goes to step 145 in which it deletes the first addressfrom the connection address list in node X's ancestor database (and, inone example, and for a purpose which will become clear when discussingreconfiguration events below, sets its reconfiguration flag buffer 136to the lowest propagation rating). At this time node B, in the presentexample, becomes the first node on the connection address list. Thennode X goes back to step 141 and repeats the routine described above.Note that because of node D's leaving the distribution network, areconfiguration event was triggered which resulted in node G changingfrom a fourth level node 15 to a third level node 14.

In step 143, if the prospective parent node has no room for the new node(e.g., the capacity of the prospective parent node is fully occupied),the new node goes to step 146, in which it receives a new connectionaddress list from the prospective parent. The prospective parent maythen perform a Fully Occupied Parent's Connection Instruction Routine,discussed below in connection with FIG. 18, wherein it creates the newconnection address list based on topology data obtained from itsprogeny. That new list may include the path back to the server throughthe prospective parent just in case, as discussed above, there are usernode departures along the path.

Of note, by having a prospective parent node prepare the new connectionaddress list as described in this example, the burden on the server isreduced and is distributed among the user nodes.

Still referring to the example depicted in FIG. 8, when node X gets tostep 143, node B will respond that it has no room and node X willproceed to step 146. When node X performs step 146, the new connectionaddress list it receives from node B will be G-B-A-S. Then node Xproceeds to step 141 and repeats the routine from that point on. Whenthe routine is performed on the topology shown in FIG. 8, step 143 willresult in node G responding that it has room for node X. Node X willthen perform step 144 and be connected to the distribution networkthrough node G as shown in FIG. 9. Here, node X becomes a fourth levelnode 15.

The distribution software may include a Return to Server Subroutine,comprised of steps 151, 152 and 153 as shown in FIG. 15, as part of theProspective Child Node's Connection Routine. This subroutine reduces therisk that a prospective child node would enter into an endless cycle offruitless attempts to dock with nodes in a particular tree. If theanswer to the query in step 143 is “no,” then node X goes to step 151 inwhich it increments by one the connection attempt counter 135 in nodeX's memory. Then node X goes to step 152 in which it determines whetherthe connection attempt limit has been reached. In one example (whichexample is intended to be illustrative and not restrictive), the limitmay be preset at any number greater than one and may depend upon whatthe designer of a particular distribution network determines would be areasonable amount of time for a node to attempt to make a connection ona particular tree, or a branch of a tree, before that node should begiven an opportunity to obtain a completely new connection address listdirectly from the server. If the connection attempt limit has not beenreached, then node X proceeds with step 146 as discussed above. If theconnection attempt limit has been reached, then node X goes to step 153,in which it goes back to the server and begins the connection routineagain as discussed above in connection with FIG. 6. If docking with aparent node is successful, then after step 144 node X performs step 154in which the connection attempt counter is set to zero.

Referring now to FIG. 16, a flow diagram associated with this exampleillustrating the Prospective Parent Node's Connection Routine is shown.Using the example illustrated in FIGS. 6, 8 and 9, when node X queriesnode B in step 142 during the Prospective Child Node's ConnectionRoutine, node B may begin performing the Prospective Parent Node'sConnection Routine. In step 161, in response to node X's query, node Bdetermines whether it is part of the distribution system node X seeks tojoin. If node B were not part of the distribution network, it wouldrespond in the negative to node X's query and node B would be finishedwith the Prospective Parent Node's Connection Routine. In the example ofFIG. 8, the answer is “yes” and node B proceeds to step 162.

In step 162 node B determines whether it has room for a new node. If theanswer were “yes,” node B would proceed to step 163 where it would allownode X to dock with it, and node B would begin transmitting to node Xdata (e.g., streaming media) originating from the server. In the exampleillustrated in FIG. 8, the answer is “no,” and node B, acting as aninstructing node, goes to step 164 where it performs the Fully OccupiedParent's Connection Instruction Routine (discussed below) and providesthe prospective new child node (here node X) with a new connectionaddress list. As noted above, the new connection address list mayinclude the path back to the server through the node B (the prospectiveparent in this example) in the event that there are user node departuresalong the path, which departures may include node B.

After performing step 164 the temporary connection between node B andnode X is terminated, and node X is sent on its way. In the example ofFIGS. 8 and 9, the new connection address list is G-B-A-S. When node Xapproaches node G, node G performs the Prospective Parent Node'sConnection Routine discussed above. In the example illustrated in FIGS.8 and 9, node G allows node X to dock with it.

Referring now to a “Distribution Network Construction” example (whichexample is intended to be illustrative and not restrictive), it is notedthat under this example the length of the distribution chains (i.e., thenumber of levels of user nodes linked through each other to the rootserver) is aimed to be kept as small as possible.

Assuming that all new user nodes have the same re-transmissioncapability (or disregarding the different re-transmission capabilitieswhich different new user nodes may have), the user nodes would bedistributed in this example through the first level until all the directconnection slots to the server were filled. Then as new user nodessought connection to the distribution network, they would be assigned toconnections with the first level nodes 12 until all the slots availableon the first level nodes were filled. This procedure would be repeatedwith respect to each level as more and more new user nodes attempted toconnect to the distribution network. In other words, the server, actingas an instructing node, would perform a Server's Connection InstructionRoutine in which one step is determining whether there is room on theserver for a new user node and, if so, the server would instruct the newuser node to connect directly to the server. If there were no room onthe server, then the server would perform the step of consulting itsnetwork topology database and devising a connection address list havingthe fewest number of connection links to a prospective parent user node.After performing the Server's Connection Instruction Routine, the serverwould either allow the new user node to dock directly with the server orsend the new user node on its way to the first prospective parent usernode on the connection address list.

In this example (which example is intended to be illustrative and notrestrictive), a partially occupied potential parent node in a particularlevel (i.e., a prospective parent node already having a child but stillhaving an available slot for an additional child node) may be preferredover unoccupied (i.e., childless) potential parent nodes on the samelevel. This may help to keep the number of interior nodes (i.e., thenumber of nodes re-transmitting data) to a minimum.

Alternatively, in another example (which example is intended to beillustrative and not restrictive), nodes that have zero children may bepreferred over nodes that already have one child. While it is true thatthis may increase the number of repeat nodes, what the inventors havefound is that by filling the frontier in an “interlaced” fashion,connecting nodes build up their buffers more quickly (allowing areduction in the incidence of stream interruptions).

Referring now to FIGS. 12A-12C, these FIGS. illustrate, in this example,what happens when a partially occupied parent node is preferred over aparent childless node as a destination address for a new user node(assuming all other factors are equal). FIG. 12A is a schematic diagramassociated with this example showing a topology wherein nodes C and D,both third level nodes 14, have remaining capacity for one or more childnodes. Server 11 has the choice of sending new user node X to eithernode C, as shown in FIG. 12B, or node D, as shown in FIG. 12C, withoutincreasing the length of the longest chain in the distribution network.However, user nodes are free to leave the distribution network at anytime. With the topology shown in FIG. 12C, if either of nodes C or Dleaves the network, there would be an effect on a child node. With thetopology shown in FIG. 12B, there is a significant chance that if one ofnodes C and D leaves the network, there would be no impact on any childnodes. That is, if it is node D that leaves the network, there is nochild which would be made an orphan.

Of note, in discussing the examples illustrated in FIGS. 6-9 and12A-12C, it has been presumed that all of the user nodes are equallycapable of simultaneously re-transmitting two copies of the contentdata. However, the user nodes actually joining a distribution networkwill have various capabilities for re-transmitting data. Some will haveno reliable capability because of hardware limitations. Other user nodeswill have high nominal capability because of their hardware and type ofInternet connection, but may have low reliability because of poor lineconditions or the vagaries of the desires of the humans actually usingthe user nodes. For example, a user node having a T1 or fasterconnection to the Internet has a significantly large bandwidth, but isnot reliable if the user (or viewer) is merely sampling the contentavailable on the distribution network.

As noted above, in one example the user nodes having the greatestreliable capability should be placed as high up in a distribution chainas possible (i.e., as far uptree as possible) because they would havethe ability to support the greatest number of child nodes, grandchildnodes and so on.

Thus, to differentiate the reliable capabilities of user nodes, a numberof factors may be considered. Examples of such factors (which examplesare intended to be illustrative and not restrictive), include following:

-   -   One is time, that is, the number of seconds (or other units of        time) since the node made its most recent connection to the        network. Everything else being equal, a user node which has been        continuously connected to the distribution network for a long        period of time may be considered under this example to be likely        more reliable (either because of line conditions or user        interest) than a user node which has been continuously connected        to the network for a short period of time.    -   Another factor is bandwidth rating, which may be determined, for        example, by actual testing of the user node when it first        attempts to connect to the server or a parent node (e.g., at        initial connection time) or determined by the nominal bandwidth        as determined by the type of connection made by the user node to        the Internet. In one example (which example is intended to be        illustrative and not restrictive), we will describe ratings        based on nominal bandwidth as follows:        -   A user node with a 56 Kbits/sec dialup modem connection to            the Internet is essentially useless for re-transmission of            content data because of its small bandwidth. In this            example, such a node is assigned a bandwidth rating of zero            (0.0).        -   A user node with a cable modem or DSL (e.g., ADSL)            connection to the Internet may be given, in this example, a            bandwidth rating of one (1.0), because it is a common type            of node and has a nominal upstream transmission bandwidth of            128 Kbits/sec, which is large enough to potentially            re-transmit two acceptable quality copies of the content            data it receives (assuming a 50 Kbit/sec content data            stream). Such capability fits well into a binary tree            topology.        -   A full rate ISDN modem connection nominally has an upstream            bandwidth of 56 Kbits/sec and a downstream bandwidth of 56            Kbits/sec, which would potentially support acceptable            quality re-transmission of a single copy of the content data            stream (assuming a 50 Kbit/sec content data stream). For            this reason, a user node with a full rate ISDN modem            connection to the Internet may be given, in this example, a            bandwidth rating of one-half (0.5), or half the rating of a            user node connected to the Internet by a DSL (e.g., ADSL) or            cable modem connection.        -   User nodes with Ti or greater links to the Internet should            be able to support more (e.g. at least twice as many)            streams as DSL (e.g., ADSL) or cable modems, and therefore            may be given, in this example, a bandwidth rating of two            (2.0). In the event that in a distribution network parent            nodes may be assigned more than two child nodes directly            connected thereto, bandwidth ratings greater than 2.0 may be            assigned under this example to Internet connections having            greater bandwidth than T1 connections.    -   In another example (which example is intended to be illustrative        and not restrictive), other bandwidth networks (e.g., 50        Kbit/sec and 100 Kbit/sec) may be supported.    -   In another example, the bandwidth needed for a node to be        “repeat capable” may depend on the particular network to which        it is attached (upon initial connection the connecting node may        first test its upstream bandwidth and then report that bandwidth        to the network server; the server may determine whether the node        is “repeat capable” or not.    -   In another example (which example is intended to be illustrative        and not restrictive), a node may be deemed “repeat capable” if        the node is not firewalled (e.g., port 1138 is open) and the        node has sufficient bandwidth to retransmit two copies of the        incoming stream.    -   A third factor is performance. A user node's performance rating        may, in one example, be zero (0.0) if it is disconnected as a        result of a Grandparent's Complaint Response Routine (discussed        below in connection with FIG. 31). Otherwise, the user node's        performance rating, in this example, may one (1.0).

Further, in this example (which example is intended to be illustrativeand not restrictive), a user node's utility rating may determined bymultiplying connection time by performance rating by bandwidth rating.That is, in this example:

Utility Rating=Time×Performance Rating×Bandwidth Rating.

Referring once again to FIG. 13, it is seen that in this exampleinformation regarding a user node's time connected to the network,bandwidth rating, performance rating, utility rating and potentialre-transmission rating (discussed below) may be stored in the usernode's elapsed time buffer 137, bandwidth rating buffer 138, performancerating buffer 139, utility rating buffer 121 and potentialre-transmission rating buffer 122, respectively.

In another example (which example is intended to be illustrative and notrestrictive), nodes entering the network may be judged to be either“repeat capable” or “non-repeat capable” (wherein non-repeat capablenodes may be called “bumpable” nodes). Repeat capability may be basedon: (1) Upstream bandwidth (e.g., tested at initial connection); and (2)the firewall status, opened or closed, of a node. In one specificexample, if a node is either firewalled or has upstream bandwidth lessthan (approx.) 2.5 times the video streaming rate, that node will bedeemed bumpable. All nodes joining the network, whether bumpable ornon-bumpable, may be placed as close to the server as possible. However,for the purpose of placement (as described for example in the UniversalConnection Address Routine of FIG. 20), a repeat capable node can bump abumpable node when being placed in the network.

Referring now to FIG. 17 a flow diagram associated with this exampleillustrating the Server's Connection Instruction Routine is shown. Thisroutine need not necessarily rely on the new user node's utility rating.This routine may rely on the potential re-transmission rating of a usernode, which is arrived at by multiplying the user node's performancerating by its bandwidth rating. That is, in this example:

Potential Re-transmission Rating=Performance Rating×Bandwidth Rating.

Thus, in this example, the server would want to put those user nodeswith the highest potential re-transmission rating as close to the serverin a distribution chain as possible (i.e., as high uptree as possible)because they have the greatest likelihood of being able to re-transmitone or more copies of content data. On the other hand, a potentialre-transmission rating of zero in this example indicates that a usernode has no ability to (or little expected reliability in)retransmitting even one copy of content data (the server in this examplewould want to put a user node with a zero rating as far as reasonablypossible from the server in a distribution chain (i.e., as low downtreeas possible)). For the purpose of ease of discussion, in the flowdiagram example of FIG. 17 illustrating the Server's ConnectionInstruction Routine, the server is concerned about whether the potentialre-transmission rating is zero (i.e., either one or both of theperformance rating and bandwidth rating is zero) or greater than zero(i.e., both the performance rating and the bandwidth rating are greaterthan zero).

In step 171 the server node interrogates the new user node (orconnection requesting node) for its bandwidth rating and performancerating. If the new user node is really new to the distribution network,or if it has returned to the server because all of the user node'sancestor nodes have disappeared from the network, the new user node'sperformance memory will contain, in this example, a performance ratingof 1.0 (e.g., the default rating). However, if the new user node hasbeen dispatched to the server for a new connection to the networkbecause the new user node had failed to provide content data to one ofits child nodes, then, in one example, its performance memory willcontain a performance rating of zero.

In step 172, the server determines, in this example, whether thepotential re-transmission rate of the connection requesting node isgreater than zero (i.e., whether both the bandwidth rating and theperformance rating are greater than zero, or, if only the bandwidthrating is considered, whether the bandwidth rating is greater than zero(i.e., the connection requesting node is a high-bandwidth node)). If theanswer is “yes,” then the server goes to step 173 in which the serverdetermines whether it has room for the new user node. If the answer tothe query in step 173 is “yes,” then the server goes to step 174 inwhich it instructs the new user node to connect directly to the server.Then the server goes to step 102 in the Server's Connection Routine (seeFIG. 10).

If the answer to the query in step 173 is “no” (i.e., the server doesnot have the capacity to serve the new user node directly), then theserver goes to step 175. In step 175, the server, acting as aninstructing node, consults its network topology database and devises aconnection address list having the fewest number of connection links toa prospective parent node. That is, the server checks its informationregarding the nodes in the level closest to the server (i.e., thehighest uptree) to determine whether there are any potential parentnodes with space available for the new user node. If there are nopotential parent nodes with space available, then the database ischecked regarding nodes in the level one link further from the server,and so on until a level is found having at least one potential parentnode with space available for the new user node. That is, the serverdetermines which parent node with unused capacity for a child node isclosest to the server (i.e., in the highest level, with the first levelbeing the highest), and devises the connection address list from suchprospective parent node to the server. The server then goes to step 102(shown in FIG. 10).

In another embodiment of the invention, the server could skip step 172and go directly to step 173 (or it could go to step 172 and, if theanswer to the query in step 172 is “no” (i.e., either one or both of thebandwidth rating and the performance rating are zero, or, if only thebandwidth rating is considered, whether the bandwidth rating is zero(i.e., the connection requesting node is a low-bandwidth node)), theserver could go to step 175). However, this could prevent the serverfrom loading up the highest levels of the distribution chains with nodescapable of re-transmitting at least one acceptable copy of the contentdata (in contrast to if the server does perform step 172 and does goesto step 176 if the answer to the query in step 172 is “no.”).

In step 176 the server consults its network topology database anddevises a connection address list having the greatest number ofconnection links to a prospective parent node. That is, the serverchecks its information regarding the nodes in the level furthest fromthe server (i.e., the lowest downtree) to determine whether there areany potential parent nodes with space available for the new user node.If there are no potential parent nodes with space available, then thedatabase is checked regarding nodes in the level one link closer to theserver, and so on until a level is found having at least one potentialparent node with space available for the new user node. In this manner,user nodes having limited or no reliable re-transmission capability maybe started off as far from the server as possible and will have areduced effect on the overall capacity of the distribution network.

As indicated above, and as discussed more fully below, one or morereconfiguration events may have transpired since the server's topologydatabase was last updated. As a result, the first prospective parentnode which is actually present on the distribution network for the newuser node to contact may not have room for the new user node. By way ofexample (which example is intended to be illustrative and notrestrictive), when node X tries to join the distribution network havingthe topology shown in FIG. 12A, the server provides node X with thefollowing connection address list: C-B-A-S. If node C had disappearedfrom the network between the last update of the server's topologydatabase and node X's attempting to contact node C, then node E, byvirtue of a reconfiguration event, would be connected, in this example,to node B as shown in FIG. 12D. Then node X, in performing theProspective Child Node's Connection Routine discussed in connection withFIGS. 14 and 15, would contact node B. Node B, in the Prospective ParentNode's Connection Routine, discussed in connection with FIG. 16, wouldhave to answer the query of step 162 in the negative and go to step 164,in which it performs the Fully Occupied Parent's Connection InstructionRoutine.

Referring now to FIG. 18, a flow diagram associated with this exampleillustrating that routine is shown. It is similar to the Server'sConnection Instruction Routine. Since the fully occupied parent node hasalready determined that it has no room for the new user node (orconnection requesting user node), the Fully Occupied Parent's ConnectionInstruction Routine does not need to include a step in which adetermination is made regarding whether there is room for the new usernode (or connection requesting node). In the Fully Occupied Parent'sConnection Instruction Routine the fully occupied parent node, acting asan instructing node, first performs step 181 in which it interrogatesthe new user node for its bandwidth rating and performance rating. Instep 182, the fully occupied parent node determines whether thepotential re-transmission rate of the new user node is greater thanzero. (If only the bandwidth rating is considered, then it determineswhether the bandwidth rating is greater than zero (i.e., the connectionrequesting node is a high-bandwidth node).) If the answer is “yes,” thenthe fully occupied parent node goes to step 183 in which the fullyoccupied parent node consults its topology database, which contains thelatest information available to that node regarding the links from thefully occupied parent node back to the server and regarding the fullyoccupied parent node's own progeny (i.e., its children, grandchildrenetc.,) and devises a new connection address list having the fewestnumber of connection links to a new prospective parent node. That is,the fully occupied parent node checks its information regarding thenodes in the level closest to the fully occupied parent node (but notcloser to the server) to determine whether there are any potentialparent nodes with space available for the new user node. If there are nopotential parent nodes with space available, then the database ischecked regarding nodes in the level one link further from the fullyoccupied parent node (and further from the server), and so on until alevel is found having at least one potential parent node with spaceavailable for the new user node. That is, the fully occupied parent nodedetermines which new prospective parent node with unused capacity for achild node is closest to the fully occupied parent node, and devises theconnection address list from such new prospective parent node throughthe fully occupied parent node and on to the server. The fully occupiedparent node then goes to step 184 in which it provides the new user nodewith the new connection address list and disconnects the new user nodefrom the fully occupied parent.

If the answer to the query in step 182 is no (i.e., either (i) one ofthe bandwidth rating and performance rating is zero or (ii) if only thebandwidth rating is considered, the bandwidth rating is zero (i.e., theconnection requesting node is a low-bandwidth node)), the fully occupiedparent node goes to step 185. In step 185 the fully occupied parent nodeconsults its network topology database and devises a connection addresslist having the greatest number of connection links to a new prospectiveparent node. That is, the fully occupied parent node checks itsinformation regarding the nodes in the level furthest from it (andfarther from the server than it is) to determine whether there are anypotential parent nodes with space available for the new user node. Ifthere are no potential parent nodes with space available, then thedatabase is checked regarding nodes in the level one link closer to thefully occupied parent node, and so on until a level is found having atleast one potential parent node with space available for the new usernode. As discussed above, this helps assure that new user nodes havinglimited or no reliable re-transmission capability are started off as farfrom the server as possible. After the fully occupied parent nodedevises the connection address list from such new prospective parentnode through the fully occupied parent node and on to the server, thefully occupied parent node then goes to step 184 where it performs asdiscussed above.

In another embodiment of the invention, the distribution software couldbe designed such that a fully occupied parent performs an abbreviatedFully Occupied Parent's Connection Instruction Routine, in which steps181, 182 and 185 are not performed. That is, it could be presumed thatthe server has done the major portion of the work needed to determinewhere the new user node should be placed and that the fully occupiedparent user node need only redirect the new user node to the closestavailable new prospective parent. In such event, only steps 183 and 184would be performed.

In the example discussed above in which node C had disappeared from thenetwork when new user node X had been given, by the server, connectionaddress C-B-A-S, and in which node B is a fully occupied parent node asshown in FIG. 12D, node B would appear to have the choice of devisingeither connection address list D-B-A-S or E-B-A-S regardless of whetherthe full or abbreviated Fully Occupied Parent's Connection InstructionRoutine were performed.

In this regard, to determine which connection address list to choosewhen there are two or more prospective parent nodes in a particularlevel having space for a new user node, the distribution software couldhave an additional subroutine as part of steps 175, 176, 183 and 185. Anexample of this subroutine, called the Multi-Node Selection Subroutineis illustrated in FIG. 19.

In step 191 the server or fully occupied parent node deciding where tosend a new user node determines whether any of the potential new parentnodes is partially occupied. As discussed earlier, in one example apartially occupied potential parent node may be preferred over anunoccupied potential parent node. In this case, if any of the potentialparent nodes is partially occupied, then the server or fully occupiedparent node goes to step 192. In step 192 the partially occupiedprospective parent node with the highest utility rating is selected asthe new prospective parent node. If there were only a single partiallyoccupied potential parent node, then that node is selected.

If in step 191 it is determined that there are no partially occupiedpotential parent nodes, then the server or fully occupied parent nodegoes to step 193. In step 193 the unoccupied prospective parent nodewith the highest utility rating is selected as the new prospectiveparent node.

In another example (which example is intended to be illustrative and notrestrictive), the software engineer could have step 193 follow anaffirmative response to the query in step 191 and step 192 follow anegative response; in such event, unoccupied prospective parent nodeswould be selected ahead of partially occupied prospective parent nodes(all other things being equal, it may be advantageous to select nodesthat have zero children over nodes that already have one child; while itis true that this may increase the number of repeat nodes, what theinventors have found is that by filling the frontier in an “interlaced”fashion, connecting nodes build up their buffers more quickly (allowinga reduction in the incidence of stream interruptions).

After whichever of steps 192 and 193 is completed, the server or fullyoccupied parent node returns to the step from which it entered theMulti-Node Selection Subroutine (i.e., step 175, 176, 183 or 185), andcompletes that step.

So, in the example shown in FIG. 12D, where node C left the networkthereby leaving node B with the chore of devising a new connectionaddress list for node X, node B would perform the Fully OccupiedParent's Connection Instruction Routine. Regardless of the bandwidth andperformance ratings of node X, node B would be choosing between nodes Dand E in the third level. In step 191 node B would determine thatneither D nor E is partially occupied, and therefore node B would go tostep 193. Assuming that nodes E and D have equal bandwidth andperformance ratings and that node D was connected to the network longerthan node E, node D would be selected because it would have the higherutility rating since it was connected to the network longer than node E.Node B would then go to step 194 and then return to the step from whichit entered the Multi-Node Selection Subroutine. When node B returns tostep 183 or 185, it completes that step and moves on to step 184. Inthat step, node B provides new user node X with new connection addresslist D-B-A-S and node X connects to the distribution network as shown inFIG. 12E.

Referring now to an “Alternative Distribution Network Construction”example (which example is intended to be illustrative and notrestrictive), it is noted that under this example the length of thedistribution chains (i.e., the number of levels of user nodes linkedthrough each other to the server) is aimed to be kept as small aspossible.

Also under this example, user nodes having the highest bandwidthcapabilities are aimed to be kept closer to the server (e.g., in orderto allow the greatest expansion of the distribution system). However, itis possible that zero bandwidth rated nodes may nevertheless appearrelatively far uptree (thereby stunting the growth of that chain). Thefollowing method may be used in constructing the distribution networkboth by servers and by prospective parents which are actually completelyoccupied, either of which may be thought of as an instructing node (thatis, software enabling the routines discussed below could be installed onservers and user nodes alike).

More particularly, in the distribution system of this example, eachchild node reports directly to (or is tested by) its parent node withrespect to information relating to the child node's bandwidth rating,performance rating, potential re-transmission rating and utility rating.In turn, each parent node reports all the information it has obtainedregarding its child nodes on to its own parent node (a parent node alsoreports to each of its child nodes the address list from that parentback to the server, which list forms what may be referred to as theancestor portion of the topology database—in addition, a parent nodereports to each of its child nodes the addresses of their siblings). Thereports occur during what may be referred to as a utility rating event.Utility rating events may occur, for example, on a predeterminedschedule (e.g., utility rating events may occur as frequently as everyfew seconds). As a result of all the reporting, each node stores in itstopology database the topology of the tree (including all its branches)extending below that node, and the server stores in its topologydatabase the topology of all the trees extending below it. This may bereferred to as the descendant portion (or descendant database) 133 ofthe topology database (see FIG. 13). The descendant database of aparticular node may include a descendant list, a list of the addressesof all the nodes cascadingly connected below that particular node.Included in the topology database information may be the utility ratingsof the nodes below the node in which that particular topology databaseresides.

After each reporting event in this example, each parent node (includingthe server), acting as an instructing node, devises two lists ofprospective (or recommended) parent nodes. In this example, the firstlist, or Primary Recommended Parent List (“PRPL”), stored in the PrimaryRecommended Parent List buffer 123 (see FIG. 13), lists all the nodes inthe descendant portion of that node's topology database which havebandwidth available to support another child node (in one example (whichexample is intended to be illustrative and not restrictive), in a binarytree system, all nodes in the descendant portion of the topologydatabase having (i) a bandwidth rating of at least one and (ii) lessthan two child nodes would be listed). They would be listed with thosenode's which are closest to the node in which that particular topologydatabase resides at the top of the list, and those nodes which are inthe same level would be ranked such that the node with the highestutility rating would be listed first, the node with the second highestutility rating would be listed second and so on. By way of example(which example is intended to be illustrative and not restrictive), thePRPL of a second level node would list a third level node with availablebandwidth ahead of a fourth level node with available bandwidth even ifthe fourth level node's utility rating were higher than that of thethird level node.

The second list in this example, or Secondary Recommended Parent List(“SRPL”), stored in the Secondary Recommended Parent List buffer 124(see FIG. 13), lists all the nodes in the descendant portion of thatnode's topology database which have the ability to re-transmit contentdata to child nodes but are fully occupied, and at least one of itschild nodes is incapable of re-transmitting content data to anotherchild node (in one example (which example is intended to be illustrativeand not restrictive), in a binary tree system, all nodes in thedescendant portion of the topology database having (i) a bandwidthrating of at least one and (ii) at least one child node having abandwidth rating less than one (i.e., being incapable of re-transmittingcontent data to two child nodes) would be listed). Like the nodes in thePRPL, the nodes in the SRPL would be listed with those node's which areclosest to the node in which that particular topology database residesat the top of the list, and those nodes which are in the same levelwould be ranked such that the node with the highest utility rating wouldbe listed first, the node with the second highest utility rating wouldbe listed second and so on.

Of note, in this example the SRPL lists those parent nodes having thegrowth of their branches (i.e., their further progeny) blocked orpartially blocked by a low-bandwidth child node. This may lead to anunbalanced growth of the distribution system, and a limitation on thetotal capacity of the system.

Of further note, to the extent that a node (including a server) has roomfor another child node or is the parent of a low bandwidth node, it maybe listed on its own PRPL or SRPL.

Referring now to FIGS. 20A and 20B, an example flow diagram illustratingwhat may be referred to as the Universal Connection Address Routine isshown. As indicated above, a server or a fully occupied prospectiveparent node receiving a connection request may be referred to as an“instructing node.” When a new node (here node N) approaches aninstructing node, the instructing node performs step 201, it receives aconnection request. It then goes to step 202 in which it interrogates ortests node N to determine whether it is a low-bandwidth node(“low-bandwidth” may mean, for example, either or both: (1) a node thatis incapable of broadcasting two copies of its incoming stream on to itschildren; and (2) a node that is incapable of rebroadcasting its streambecause it is firewalled). In the binary tree system of one example, alow-bandwidth node is a node with a bandwidth rating less than one. Ifnode N is a low bandwidth node, the instructing node proceeds to step203 in which the instructing node determines whether there are anyavailable prospective parent nodes which are not fully occupied.Sometimes the distribution network may be fully occupied. If it is, theinstructing node's PRPL will be empty. If it is empty, the response tothe query in step 203 would be yes. Then the instructing node goes tostep 209 in which the new node is sent back to the server to start theconnection process from the beginning. If the response to the query instep 203 is no, then the instructing node goes to step 204 in which itselects a prospective (or recommended) parent node for node N. Theinstructing node then moves on to step 205 in which it consults itstopology database and devises a connection address list from therecommended parent node back to the server, and provides such connectionaddress list to node N. (If the instructing node is a user node, thenthe connection address list leads back to the server through theinstructing node.) At this point, node N performs the Prospective ChildNode's Connection Routine discussed above in connection with FIG. 14.

As part of step 205, the instructing node inserts node N into itstopology database as a child of the recommended parent node. It doesthis because other new nodes may seek connection instructions prior tothe next utility rating event (i.e., before reports providing updatedinformation regarding the topology of the distribution network arereceived by the instructing node), and such new nodes should not be sentto a prospective parent which the instructing node could know is fullyoccupied. In this regard, the instructing node then goes to step 206 inwhich it checks its topology database to determine whether therecommended parent, with node N presumptively docked to it as a childnode, is fully occupied (in the example here of a binary tree network,whether it has two child nodes). If the answer is no, then theinstructing node has finished this routine. If the answer is yes, thenthe instructing node goes to step 207 in which it removes therecommended parent from the PRPL and inserts it into the SRPL, and theinstructing node has finished the routine.

If the answer to the query in step 202 is no (e.g., node N is not alow-bandwidth node; in the binary tree network example it is ahigh-bandwidth node capable of re-transmitting content data to two childnodes), the instructing node moves on to step 208. There it determineswhether both the PRPL and SRPL are empty (which may occur under certaincircumstances, such as, for example, when the number of levels in adistribution system is capped and at least all the nodes on all but thelast level are fully occupied with high-bandwidth nodes). If so, theinstructing node goes to step 209 in which the new node is sent back tothe server to start the connection process from the beginning. If theresponse to the query in step 208 is no, then the instructing node goesto step 210 in which it selects a prospective (or recommended) parentnode for node N from the PRPL and an alternate recommended parent nodefrom the SRPL (if either the PRPL or SRPL is empty, the instructing nodewill make a “nil” selection from that list—the instructing node knowsfrom step 208 that at least one of the lists will not be empty). Theinstructing node then goes to step 211 in which it determines whetherthe alternate recommended parent node is closer to the server (i.e.,higher uptree) than the recommended parent node derived from the PRPL.If the alternate recommended parent node is on the same level as, or ona lower level than the recommended parent node derived from the PRPL (orif the selection from the SRPL is nil), then the answer to the query instep 211 is no.

In such event, the instructing node goes to step 212 in which itconsults its topology database and devises a connection address listfrom the recommended parent node back to the server, and provides suchconnection address list to node N (if the instructing node is a usernode, then the connection address list leads back to the server throughthe instructing node).

As in step 205 discussed above, at this point, node N performs theProspective Child Node's Connection Routine discussed above inconnection with FIG. 14, and in step 212, the instructing node insertsnode N into its topology database as a child of the recommended parentnode.

The instructing node moves to step 213 in which it adds node N to anappropriate position on the PRPL. It does this because, as a result ofstep 202, it knows that the node N is capable of re-transmitting contentdata to its own child nodes.

The instructing node then goes to step 214 in which it checks itstopology database to determine whether the recommended parent, with nodeN presumptively docked to it as a child node, is fully occupied (in theexample here of a binary tree network, whether it has two child nodes).If the answer is no, then the instructing node has finished thisroutine. If the answer is yes, then the instructing node goes to step215 in which it removes the recommended parent from the PRPL because itis now deemed to not be an available prospective parent node.

Then the instructing node goes to step 216 in which it consults itstopology database to determine whether any of the recommended parentnode's children is a low-bandwidth node (in this example, knowing thatnode N is not a low-bandwidth node and knowing that the recommendedparent node has two child nodes, the question is whether the child nodeother than node N is a low-bandwidth node.) If the answer is no (i.e.,all the recommended parent node's children are high-bandwidth nodes),then the instructing node has finished the routine.

If the answer is yes, then the growth of the recommended parent node'sline of progeny is partially blocked by a low-bandwidth child node. Theinstructing node moves on to step 217 in which it adds the recommendedparent to the SRPL.

If the answer to the query in step 211 is yes (i.e., the alternaterecommended parent (selected from the SRPL) is: (i) on a higher levelthan the recommended parent (selected from the PRPL) or (ii) theselection from the PRPL is nil), then the instructing node moves to step218. In that step the instructing node consults its topology database todetermine: (i) which of the alternate recommended parent node's childnodes is a low-bandwidth node or (ii) if they both are low-bandwidthnodes, which of the child nodes has been connected to the system ashorter period of time. In one example (which example is intended to beillustrative and not restrictive), the instructing node may send adisconnect signal to that child node with instructions to return to theserver to start the connection process from the beginning (as a new usernode (or connection requesting user node)). In another example (whichexample is intended to be illustrative and not restrictive), the bumpednode may climb its path to its grandparent which gives it a newconnection path—rather than returning to the root server (doing sotypically means that the incoming node that bumped thenon-repeat-capable node ends up being that node's new parent).

The instructing node moves on to step 219 in which it consults itstopology database and devises a connection address list from thealternate recommended parent node back to the server, and provides suchconnection address list to node N (if the instructing node is a usernode, then the connection address list leads back to the server throughthe instructing node).

As in steps 205 and 212 discussed above, at this point, node N performsthe Prospective Child Node's Connection Routine discussed above inconnection with FIG. 14, and in step 219, the instructing node insertsnode N into its topology database as a child of the alternaterecommended parent node.

The instructing node moves to step 220 in which it adds node N to anappropriate position on the PRPL. It does this because, as a result ofstep 202, it knows that the node N is capable of re-transmitting contentdata to its own child nodes.

The instructing node then goes to step 221 in which it checks itstopology database to determine whether all the child nodes of thealternate recommended parent are high-bandwidth nodes. If the answer isno, then the instructing node has finished this routine. If the answeris yes, then the instructing node goes to step 222 in which it removesthe alternate recommended parent from the SRPL because it is now deemedto not be an available alternative prospective parent node since thegrowth of its progeny line is not even partially blocked by one of itsown children. At this point the instructing node has finished theroutine.

With the routines discussed in connection with the above examples, thedistribution network will be built with each new node assigned to theshortest tree (or chain), and those with the fewest number of linksbetween it and the server. However, low-bandwidth nodes, which wouldtend to block the balanced growth of the distribution network, would bedisplaced by high-bandwidth nodes and moved to the edges of the networkwhere they would have reduced effect on the growth of the network.

Referring now to FIG. 21, this FIG. may be used as an example toillustrate how the Universal Connection Address Routine works. It showsprimary server 11 with node A as first level node 12, its child nodes Band C as second level nodes 13, their child nodes D, E, F and G as thirdlevel nodes 14, node D and G's child nodes H, I, J and K as fourth levelnodes 15, and node I's child nodes L and M as fifth level nodes 17.Assume for this example that all available docking links directly to theserver 11 are occupied by high-bandwidth nodes, and that all trees areat full capacity other than that rooted to the server 11 through firstlevel node A. The utility rating for each node is set forth in FIG. 21under its letter designation. Low-bandwidth nodes (in this example,those nodes having a bandwidth rating less than one) are shown with abandwidth rating of “a,” which indicates in this example that such nodeswill not have any child nodes assigned to them. Nodes A, B, C, D, E, G,I, J and K are high-bandwidth nodes (or repeater nodes (i.e., they arecapable of re-transmitting the content data they receive from theirrespective parent nodes to their respective child nodes, if any)).

A new user node (or other connection requesting user node), herereferred to as “node N”, may be directed to node A as a result ofvarious reconfiguration events. When node A receives a connectionrequest from node N, node A will, in this example, either consult bothof its PRPL and SRPL buffers, if node N is a high-bandwidth node, orconsult just its PRPL buffer (if node N is a low-bandwidth node).

Nodes F, H, L, and M will not appear on any list in this example sincethey are low-bandwidth nodes. Nodes B, C, D, G, I and A itself will notappear on the PRPL in this example since these nodes are fully occupied.However, nodes C, D, and I will appear on the SRPL in this examplebecause they each have at least one low bandwidth child node.

Using the rules discussed above (i.e., ranking prospective parent nodesby level and within levels by utility rating) the PRPL would be asfollows in this example:

PRPL

-   -   E (a third level node with available capacity)        -   J (the fourth level node with available capacity having the            highest utility rating)    -   K (a fourth level node with available capacity)

The SRPL in this example would be as follows:

SRPL C (the fully occupied second level node with a low-bandwidth childnode)

-   -   D (the fully occupied third level node with a low-bandwidth        child node)    -   I (the fully occupied fourth level node with a low-bandwidth        child node)

If node N is a low-bandwidth node, node A will give, in this example,node N the following as its new connection address list:

-   -   E-B-A-S. Since node E would not have two child nodes, it would        remain on the PRPL.

If node N is a high-bandwidth node, node A will compare (step 211 ofFIG. 20B) the first node on the PRPL (the recommended parent node) withthe first node on the SRPL (the alternate recommended parent node).Here, node C, the first node on the SRPL is a higher level node thannode E, the first node on the PRPL. So, node A will send a disconnectsignal (step 218 of FIG. 20B) to node F, node C's low-bandwidth childnode. Then it will provide node N with the following new connectionaddress list and add node N to the PRPL (step 219 of FIG. 20B):

C-A-S.

Since node C would now have two high-bandwidth child nodes (nodes N andG), node C would be removed from the SRPL (step 222 of FIG. 20B).

Further, in this example wherein node N is a high-bandwidth node, whennode F returns to the server 11 (or, in another example, goes to Node A)for a new connection, the server (or Node A) will also use the UniversalConnection Address Routine (Node F may go to Node A rather than theserver because (in one example) when a node is “kicked” it may climb itsinternal connection path rather than jumping directly to the rootserver). Since node F is a low-bandwidth node, the server (or Node A)will give node F the following as its new connection address list:

E-B-A-S.

FIG. 22 illustrates the new topology. As can be seen, absent interveningevents, low-bandwidth node F will end up moving down from the thirdlevel to the fourth level and the bandwidth capacity of the third levelwill increase from six child nodes to eight (its maximum in this binarytree example). The potential bandwidth capacity of the fourth levelwould also increase, from ten child nodes to twelve.

Referring now to a “Distribution Network Reconfiguration” example (whichexample is intended to be illustrative and not restrictive), it is notedthat under this example the user nodes are free to exit the distributionnetwork at will. And, of course, user nodes may exit the distributionnetwork due to equipment failures between the user node and thecommunication network (the Internet in the examples discussed herein).This was first discussed in connection with FIGS. 10A-E.

Under this example the present invention may handle the reconfigurationrequired by a user node departure by having certain user nodes in thesame tree as the departing node perform a Propagation Routine. Theresults of the propagation routine of this example are illustrated inFIGS. 23 and 24. There a tree rooted to the server through first leveluser node P is illustrated. Node P has two child nodes, second levelnodes Q and X. Through node X, P has two grandchild nodes, third levelnodes A and B. Based on the relative utility ratings of nodes Q and X, Phas sent signals to its children instructing them to set the color ofthe flag represented by the information in their respectivereconfiguration flag buffers to “green” and “red,” respectively. The useof colors as designators is merely discretionary. In reality theyrepresent relative ratings of siblings for purposes of determining theirroles in a reconfiguration event, and may be referred to as “propagationratings.” In addition, instead of colors, numbers (e.g., 1 and 2) couldbe used, as well as any of many other nomenclature schemes to describethe grades of propagation ratings. The “red” “green” ratings discussedherein shall be deemed representative of all such schemes. The number ofgrades of propagation ratings assigned by a parent node may be equal tothe number of children each parent node has. For example, for a branchfactor “n” system, the maximum number of grades of propagation ratingsmay be “n.” Since the distribution network in the examples discussedherein is a binary tree distribution network, a parent node will berequired to assign at most up to two grades of propagation ratings.

In the example shown in FIG. 23, node P, during the most recent utilityrating measurement event, discerned that node Q has a higher utilityrating than node X, and therefore P has assigned node Q a green rating,represented by the solid-lined circle surrounding the letter Q in FIG.23. P has assigned node X a red rating, represented by the dashed-linedcircle surrounding the letter X in FIG. 23. In a similar manner, node Xhas assigned green and red ratings to third level nodes A and B,respectively. In this example (which example is intended to beillustrative and not restrictive), at the same time that a parent nodeassigns a propagation rating to a child node, it may also provide tosuch child node the address of the child node's sibling, if there isany. A child node may store information about its sibling (or siblings)in the sibling portion (or sibling database) 134 of its topologydatabase (see FIG. 13). The sibling database includes a sibling list, alist of the addresses of a node's siblings (the data relating to thesiblings' addresses may also contain information regarding thepropagation ratings of the siblings (e.g., in the event that thedistribution system has a branch factor greater than two)). In theexample shown in FIG. 23, nodes Q and X know that they are each other'ssiblings and nodes A and B know that they are each other's siblings.

In another example (which example is intended to be illustrative and notrestrictive), nodes do not store information about their siblings. Inother words, in this example, a node generally does not know who itssibling is. Instead, cross connections between a red node and its greensibling are implemented via a “priority join” message sent to a redchild that includes the IP address of the green sibling as the firstentry in the connection path list.

In the event that node X were to leave the distribution network, nodes Aand B would of course stop receiving content data from node X. Nodes Aand B would consult their topology databases for the address of theirgrandparent, and each would interrogate node P for instructions. Sincenode X is out of the distribution network, node P would send out areconfiguration event signal (sometimes referred to as a “propagationsignal”) to the nodes which had been node X's children (i.e., the nodeswhich were node P's grandchildren through node X) and node P would sendan upgrade propagation rating signal to its remaining child, here nodeQ.

In response to the upgrade propagation rating signal, node P's remainingchild, node Q, would set its reconfiguration flag buffer 136 (see FIG.13) to the next highest available propagation rating grade. Since in theexample illustrated in FIG. 23, node Q's reconfiguration flag bufferalready is set for the highest propagation rating grade (here green),node Q could either do nothing or reset its propagation rating inresponse to the upgrade propagation rating signal. The result would bethe same, node Q's propagation rating would remain green. If node Q'spropagation rating were red, then it would set its propagation rating togreen in response to the upgrade propagation rating signal. Node Q woulddo nothing else in response to the upgrade propagation rating signal(note that as a matter of design choice, the software engineer couldhave the parent of the departed node (here node P is the parent ofdeparted node X) send no upgrade propagation rating signal to itsremaining child node (here node Q) if its remaining child node alreadyis at the highest propagation rating).

In this example, the recipients of the propagation signal (i.e., thechildren of the missing node) would respond thereto as follows. Firstthey would check their own respective propagation ratings. If thepropagation signal's recipient has the highest propagation rating grade(here green), it would reset its propagation rating to the lowest ratinggrade (here red); re-transmit the propagation signal to its own childnodes (if there are any); disconnect the child node which did not havethe highest propagation rating prior to its receipt of the propagationsignal if the propagation signal's recipient with the green rating hasmore than one child node; allow its sibling to dock with it as a childnode for the purpose of transmitting content data to that child node;and dock (or remained docked), for purposes of receiving content data,with the node sending the propagation signal to it (in systems having abranch factor of more than two, the propagation signal recipient whosepropagation rating had been the highest would disconnect its child nodeswhich did not have the highest propagation rating, prior to the receiptof the propagation signal just sent, and it would allow its (i.e., theformerly green node's) siblings to dock with it as child nodes).

If the propagation signal's recipient has other than the highestpropagation rating (i.e., just prior to the receipt of the propagationsignal), it would upgrade its propagation rating to the next highestrating grade; dock with its sibling which had the highest rating grade;and begin receiving content data from it. If the propagation signal'srecipient has other than the highest propagation rating, it does notre-transmit the propagation signal to its own child nodes.

In the example illustrated in FIG. 23, nodes A and B receive thepropagation signal from node P. Since node A has the highest propagationrating grade, here green, it: (i) sets its reconfiguration flag buffer136 (see FIG. 13) so that it has the lowest propagation rating grade,here red; and (ii) docks with node P (becoming a second level node 13)to begin receiving content data from node P. Node B changes itspropagation rating from red to the next higher propagation rating (andsince this example is a binary tree (or branch factor two) system, thenext higher rating is the highest, green) and docks with node A toreceive content data. The resulting topology is shown in FIG. 24. Notethat node B remains a third level node 14.

FIGS. 25 and 26 illustrate what happens in this example when thedeparting node is green. In FIG. 25, node X is the departing node and itis green. When node P sends the upgrade propagation rating signal tonode Q, it changes its propagation rating from red to green. In otherrespects the reconfiguration event proceeds essentially as described inthe paragraph immediately above, and results in the topology shown inFIG. 26 (which is the same as the topology in FIG. 24).

FIG. 27 is a flow diagram associated with an example showing the ChildNode's Propagation Routine, the routine which is followed by a childnode upon receiving a propagation signal. Of note, this example isprovided for illustration only, and is not restrictive, and otherexamples are of course possible (e.g., the color of a node may assignedby its parent such that nodes assign and know the color of theirchildren but not of themselves).

In any case, still referring to FIG. 27, the child node first performsstep 271 wherein it determines whether it has received such a signal. Ifit has not, then it does nothing. If it has received a propagationsignal, it proceeds to step 272 wherein it checks its propagation ratinggrade in reconfiguration flag buffer 136 (see FIG. 13). If itspropagation rating is at the highest grade (i.e., it is a “green” nodein this example), then it proceeds to step 273 where it sets itsreconfiguration flag buffer to the lowest propagation rating grade. Itthen proceeds to step 274 in which it re-transmits the propagationsignal to its own child nodes, and which results in the undocking of allits child nodes except for the one with the highest propagation rating.The child node (i.e., the child node referred to in the second sentenceof this paragraph) then performs step 275 in which it determines whetherit is already docked with the node which sent the propagation signal. Ifit is not (i.e., it received the propagation signal from itsgrandparent), then it proceeds to step 276. In that step it: (i) devisesa new connection address list, which is the ancestor portion of itstopology database with the current nominal parent node removed,resulting in the grandparent node becoming the first node on theconnection address list; and (ii) then performs the Prospective ChildNode's Connection Routine (i.e., it goes to step 141 discussed above inconnection with FIGS. 14 and 15). The Prospective Child Node'sConnection Routine is performed because some likelihood exists that eventhe grandparent node may have departed from the distribution systembetween the moment it sent out the propagation signal and the momentthat its highest rated grandchild from its missing child attempted todock with it.

If the answer to the query in step 275 is in the affirmative (i.e., thechild node is receiving a propagation signal which has beenre-transmitted by its parent), then the child node does nothing more (oras illustrated in FIG. 27, it performs step 277 which is to remaindocked to its parent node).

If the answer to the query in step 272 is in the negative (i.e., it doesnot have the highest propagation rating (it is a “red” node in thisexample)), then it proceeds to step 278 in which it: (i) sets itsreconfiguration flag buffer so that its propagation rating is the nexthigher grade (in this binary tree system the rating is upgraded from redto green); (ii) undocks from the parent with which it was docked beforereceiving the propagation signal (if it was docked with a parent beforereceiving such signal); and (iii) either (a) waits a predeterminedperiod of time during which the node's sibling which was green prior totheir receipt of the propagation signal should have re-transmitted thepropagation signal to its own child nodes (thereby causing any red childnodes to undock from it) or (b) confirms that the node's sibling whichwas green prior to their receipt of the propagation signal actual didre-transmit the propagation signal to its child nodes (if it has any).Then the child node performs step 279 in which it: (i) devises a newconnection address list, which is the ancestor portion of its topologydatabase with its sibling node having the highest propagation ratingplaced in front of the previous parent as the first node on theconnection address list; and (ii) then performs the Prospective ChildNode's Connection Routine (i.e., it goes to step 141 discussed above inconnection with FIGS. 14 and 15). The Prospective Child Node'sConnection Routine is performed because some likelihood exists that thesibling may have departed from the distribution system between themoment that the propagation signal had been sent to the child node andthe moment that the child node attempted to dock with its sibling.

In another example (which example is intended to be illustrative and notrestrictive), part (iii) of step 278 may be handled using the “priorityjoin” mechanism. More particularly, in this example, a priority joinfrom a node X cannot be refused by a target node T—it must accept (dock)the incoming node. If the target node T already had two children G & R,the target node T instructs its red child R to connect (via “priorityjoin”) to the green node G. The node T then disconnects from its redchild R immediately prior to accepting the incoming node X. The bumpednode R then sends a priority join to its own green sibling A as thetarget. These actions cause the reconfiguration events to cascade untilthe edge of the tree is reached (of note, the algorithm described inthis paragraph may have essentially the same effect as illustrated inFIGS. 28 and 29—under certain circumstances the algorithm described inthis paragraph may be somewhat more reliable).

FIG. 28 illustrates an example distribution system comprising node P asa first level node 12; nodes Q and X as second level nodes 13; nodes Aand B as third level nodes 14; nodes C, D, E an F as fourth level nodes15; nodes G and H as fifth level nodes 17; nodes I and J as sixth levelnodes 20; nodes K and L as seventh level nodes 21 and nodes M and N aseighth level nodes 22. Nodes Q, B, C E, H, I, L and M have redpropagation ratings, as symbolized by the dashed circles, and theremaining nodes have green propagation ratings as symbolized by thesolid circles. As a result of node X's departing from the system, node Psends out an upgrade propagation rating signal to node Q and apropagation signal to the children of node P's departed child node X(i.e., nodes A and B).

In another example (which example is intended to be illustrative and notrestrictive), during a graceful depart of node x, node x may send outmessages to its parent and children immediately prior to itsdeparture—rather than the parent of node x initiating these messages asdescribed above.

In any case, continuing the example of FIG. 28, node Q changes itspropagation rating to green. Further, in this example nodes A and Bbegin the Child Node's Propagation Routine. With respect to node A, itanswers the query of step 271 in the affirmative. Since its rating isgreen, it also answers the query of step 272 in the affirmative. In step273 node A changes the setting of its reconfiguration flag buffer toshow a red propagation rating. In step 274 it re-transmits thepropagation signal to its child nodes C and D. It answers the query ofstep 275 in the negative because it is not docked for purposes ofreceiving content data with node P. Node A then goes to step 276 whereinit consults the ancestor portion of its topology database and creates anew connection address list starting with its grandparent. The newconnection address list is P-S. Then node A performs the ProspectiveChild Node's Connection Routine, starting with step 141. (See FIG. 14.)Assuming that no other intervening events have occurred, node A willsuccessfully dock with node P.

Node B answers the query of step 271 in the affirmative and, because itspropagation rating was red when it received the propagation signal, itanswers the query of step 272 in the negative. From there it goes tostep 278 in which it changes its propagation rating to green. Then instep 279 node B consults the ancestor portion of its topology databaseand creates a new connection address list with its sibling, node A,placed in front of node X as the first address on the new connectionaddress list. The new connection address list is A-X-P-S. Then node Bperforms the Prospective Child Node's Connection Routine, starting withstep 141. Assuming that no other intervening events have occurred, nodeB will successfully dock with node A (if node A has disappeared, node Bwould attempt to dock with node X, but since it is not there, it wouldmove on to node P.)

Node A, which had the higher propagation rating of the two child nodesof departed node X, moves up one level to become a second level node 13.Since it is a “new” entry to the second level, its initial utilityrating and its propagation rating will be lower than that of node Q. Astime goes by, at subsequent utility rating measurement events node A'sutility rating (and hence its propagation rating) may become higher thanthat of node Q.

Node B, which had the lower propagation rating of the two child nodes ofdeparted node X, does not re-transmit the propagation signal to itschild nodes (nodes E and F), and they will follow B wherever it goes inthe distribution system. In the example discussed here, node B becomesthe child of node A while remaining third level node 14. At leastinitially, it will be node A's child with the higher utility rating andpropagation rating.

As a result of node A's performing step 274, its child nodes C and D(which were fourth level nodes 15 in FIG. 28 when node X was still inthe system) receive a propagation signal. Since node C has a redpropagation rating, it, like node B, will remain in its level, changeits propagation rating to green and dock with its sibling, with theresult being that node D becomes its parent.

Since node D had a green propagation rating when it received thepropagation signal, it answers the queries of steps 271 and 272 in theaffirmative and changes its propagation rating to red in step 274. Itanswers the query of step 275 in the affirmative, and remains dockedwith node A. As a result, node D moves up a level and becomes an thirdlevel node 14 (with, at least until the next utility rating event, alower utility rating and propagation rating than its new sibling, nodeB).

This process proceeds down the tree, with each child of a node whichmoves up a level doing one of the following under this example: (i) ifit is a node having a green propagation rating, it remains docked withits parent, thereby itself moving up a level, changes its propagationrating to red and re-transmits the propagation signal to its childnodes; or (ii) if it is a node having a red propagation rating, it dockswith the node which was its sibling, thereby staying in the same level,and changes its propagation rating to green.

The resulting topology after the reconfiguration event caused by nodeX's departure is illustrated in FIG. 29.

Of note, it is believed that reconfiguration using the Child Node'sPropagation Routine of this example when a node departs the system doesnot necessarily result, in the long run, in significantly moreinter-node reconnection events than any other reconfiguration method(and may result in fewer reconnection events). Moreover, it is believedthat reconfiguration using the Child Node's Propagation Routine of thisexample helps assure that the more reliable nodes are promoted up thedistribution network even if many reconfiguration events occur close intime to each other in a particular tree.

Referring now to a specific example of pseudo-code (which example isintended to be illustrative and not restrictive), it is noted that apropagation routine may be set forth as follows (wherein node X is thenode departing from the distribution system):

Departs(X) Begin If (X.Parent.GreenChild = X) /* the departing node isgreen*/ { X.Parent.GreenChild := X.Parent.RedChild X.Parent.RedChild :=X.GreenChild } Else /* the departing node is already red */ {X.Parent.RedChild :=X.GreenChild } Propagate(X.GreenChild, X.RedChild)End

Referring now to another specific example of pseudo-code (which exampleis intended to be illustrative and not restrictive), it is noted that apropagation routine may be set forth as follows (wherein node promotionduring the network reconfiguration event is precipitated by node X'sdeparture):

Propagate (X, RedSibling) Begin OriginalGreenChild := X.GreenChildOriginalRedChild := X.RedChild X.RedChild := X.GreenChild X.GreenChild:= RedSibling If (OriginalGreenChild <> null) {Propagate(OriginalGreenChild, OriginalRedChild) } End

Referring now to a “Malfunctioning Nodes” example (which exampledescribes a voting system between grandchildren and grandparents about apotentially malfunctioning parent and is intended to be illustrative andnot restrictive), it is noted that what happens when a node leaves thedistribution network was discussed in the above example (e.g., when anode leaves the network, its parent will, at the next utility ratingevent, report that it has room for a new node, except when the parenthas been contacted about the missing node by its grandchild node ornodes, in which event, a reconfiguration event will proceed as describedabove). Sometimes, however, a node intends to remain in the network, butthere is a failure of communication.

In this regard, each node's topology database may include informationregarding that node's ancestors and descendants. In the event that achild node stops receiving signals from its parent node, the child may,in one example, send a “complaint” message to its grandparent. Thegrandparent may check whether the parent is still there. If it is not,then the grandparent may send a propagation signal to the child nodes ofthe missing parent.

Further, if the grandparent detects that the parent node is actuallystill there, then the grandparent node may send a disconnect signal tothe parent node (e.g., sending it back to the server to begin theconnection process again). This may occur, for example, when one of thetwo following conditions is exists: (i) the child node is the only childnode of the parent, or (ii) the child and its sibling(s) are complainingto the grandparent.

In this example, the grandparent would also send a propagation signal tothe child nodes of the disconnected parent, and a reconfiguration eventwould occur.

However, if the child node has siblings and they are not sendingcomplaint signals to the grandparent, then the grandparent may assumethat the problem is with the complaining child node. Thus, grandparentmay send a disconnect signal to the complaining child node (e.g.,sending it back to the server to begin the connection process again). Ifthe complaining child node had its own child nodes, they would contactthe departed child node's parent to complain, starting a reconfigurationevent (in another example (which example is intended to be illustrativeand not restrictive), the grandparent would send out signals to themalfunctioning parent (instructing it to depart) and to the children(instructing the green child to climb its path to its grandparent andinstructing the red child to cross connect to the green child).

The foregoing example (which example is intended to be illustrative andnot restrictive) can be described in connection with FIG. 30 (whichdepicts a tree in a binary system having a primary server 11, in whichnode A, a first level node 12, has two child nodes B and B′ (which aresecond level nodes 13); node B has two child nodes C and C′ (which arethird level nodes 14); node C has two child nodes D and D′ (which arefourth level nodes 15); and node D has two child nodes E and E′ (whichare fifth level nodes 17)) and FIG. 31 (which is a flow diagram showingan example Grandparent's Complaint Response Routine).

Who does node C complain to in this example when node C no longer getssatisfactory service from node B? Node C complains to its grandparent,node A. If node C does not hear back from node A within a predefinedamount of time (e.g., if node A has left the network), node C will thenexit the network and immediately reconnect as a new node by going to theprimary server S for assignment.

What does node A do in response to a complaint from node C in thisexample? When node A receives a complaint from grandchild node C aboutnode C's parent node B (i.e., node A's child node B), node A will chooseto either remove its child node B or its grandchild node C. A will makethis determination based on whether node C alone, or both node C and itssibling node C′ are experiencing problems with node B, together with theknowledge of whether node A is continuing to receive satisfactoryservice reports from node B. If node A is continuing to get satisfactoryservice reports from node B and there is no indication that node C′ (thesibling of node C) is experiencing problems with node B, then node Awill assign the “fault” to node C and issue a disconnect order for itsremoval. At this point the green child of node C (i.e., node D or D′)will move up a level connecting to parent B, and the red child of node C(the other of node D or D′) will connect as a child of its formersibling. The reconfiguration event will then propagate as discussedabove.

If, on the other hand, node A is not getting satisfactory servicereports in this example from node B and/or a complaint from node C'ssibling arrives within a ‘window’ of node C's complaint, then node Awill assign the “fault” to node B and issue a disconnect order for itsremoval. At this point the green child of node B (i.e., node C or C′)will move up a level connecting to grandparent node A, and the red childof node B (the other of node C or C′), will connect as a child of itsformer sibling. The reconfiguration event will then propagate asdiscussed above.

An exception to the above is the case where node C is the only child ofnode B. Under these circumstances node B may be disconnected in thisexample by node A based solely on the recommendation of node C. Inanother example, the system will not disconnect a node with one childbased solely on the complaint of that child (in this case there may beinsufficient data to accurately assign blame—disconnecting the nodebeing complained against and promoting the complainer may have thepotential to promote a node that is experiencing problems).

Referring now to FIG. 31 (showing a flowchart associated with thisexample), node A receives a complaint from node C about node B in step311. Node A then goes to step 312 in which it checks its topologydatabase to determine whether node C is the only child of node B. If theanswer is no (as shown in FIG. 30), then node A goes to step 313 inwhich node A determines whether there is a communication problem betweenit and node B. If the answer is no, then node A proceeds to step 314 inwhich it determines whether it has received a similar complaint aboutnode B from node C′ within a predetermined period of time of node A'shaving received the complaint from node C. If the answer to that queryis no, then node A goes to step 315 in which it sends a disconnectsignal to node C. At that point node A has completed the Grandparent'sComplaint Response Routine (in one example a propagation signal does notnecessarily have to sent by node A to node C's child nodes—if any exist,they will complain to node B which, upon discerning that node C is nolonger in the distribution network, will send a propagation signal tosuch complaining nodes).

If the response to any of the queries in steps 312, 313 and 314 is yesin this example, then node A proceeds to step 316 in which itdisconnects node B. Node A then proceeds to step 317 in which it sends apropagation signal to its grandchild nodes (here nodes C and C′) and areconfiguration event will occur as described above.

The method of this example described above takes a “2 out of 3” approachon the question of node removal. In this regard, it is believed thatmany interior nodes in a binary tree distribution network constructedpursuant the present invention will have direct connections to threeother nodes: their parent, their green child, and their red child. Theconnections between a node and its three “neighbor” nodes can be thoughtof as three separate communications channels. In this example a node isremoved from the network when there are indications of failure orinadequate performance on two of these three channels. When there areindications that two of the channels are working normally, thecomplaining node is presumed to be “unhealthy” and is removed.

In the case where an interior node has only a single child, the“complaint” of that child to its grandparent is sufficient, in thisexample, to remove the parent node—even when the node to be removed iscommunicating perfectly well with it's own parent. In other words, giventhe communication chain A-B-C where node A is the parent of node B andnode B is the parent of node C, and given that node C has no siblings,then a complaint of node C to node A will cause node A to remove node Bin this example regardless of the fact that node A and node B are nothaving communication problems (this course of action may help ensurethat a potentially unreliable node does not move up the hierarchy ofnodes, even at the cost of occasionally sending a “healthy” node back tothe edge of the distribution chain based on uncorroborated complaints ofits child). Of course, as mentioned above, there are examples where thesystem will not disconnect a node with one child based solely on thecomplaint of that child.

In another example of voting (which example is intended to beillustrative and not restrictive), instead of (or in conjunction with)nodes voting on the behavior of other nodes, nodes may continually gradetheir own performance and if they detect that there is insufficientbandwidth on two or more of their links (links to their parent and theirchildren) the node will perform a graceful depart from the network(initiating a reconfiguration as described elsewhere) and then the nodewill either climb its path to an ancestor node (or go directly to theserver) to request a connection path to the edge of the tree. Thissystem allows nodes to “step aside” when they detectconnection/bandwidth related issues.

Referring now to a “Stepped Delay of Playing Content Data” example(which example is intended to be illustrative and not restrictive) it isnoted that in order to have all the user nodes experience the playing ofthe content data at approximately the same time, regardless of the levelin which the node resides, the content data buffer 125 shown in FIG. 13of a user node may be larger the higher uptree it is in a distributionchain (i.e., the closer it is to the root server). The larger thebuffer, the greater the amount of time between a particular event (orfrom the node's receiving the content data), and the node's actuallyplaying the content data in its content data buffer. To the extent thatthe content data buffer of a node is sized to vary the time that theplaying of the content data is started, the content data buffer is adelay. Alternatively, the delay may be a timer or a delay buffer 126 asshown in FIG. 13, or a combination of elements. The delay's purpose maybe to help assure that all users experience the play of the content dataapproximately simultaneously.

For a distribution network having n levels of user nodes cascadinglyconnected to a server node, where n is a number greater than one (andtherefore the distribution network comprises the server node and firstthrough nth level user nodes), the period of time (i.e., the delay time)between:

(i) the moment content data is received by a node or, from apredetermined moment such as, for example, a reporting event or utilityrating event (the occurrence of which may be based on time periods asmeasured by a clock outside of the distribution system and would occurapproximately simultaneously for all nodes); and

(ii) the playing of the content data by the node;

is greater for a node the higher uptree the node is on the distributionchain. That is, the delays in first level nodes create greater delaytimes than do the delays in second level nodes, the delays in secondlevel nodes create greater delay times than the delays in third levelnodes and so on. Described mathematically, in an n level system, where xis a number from and including 2 to and including n, the delay timecreated by a delay in an (x−1) level node is greater than the delay timecreated by a delay in an x level node.

By way of example (which example is intended to be illustrative and notrestrictive), first level nodes could have a built in effective delaytime in playing content data of one hundred twenty seconds, second levelnodes could have a built in effective delay time of one hundred-fiveseconds, third level nodes could have a built in effective delay time ofninety seconds, fourth level nodes could have a built in effective delaytime of seventy-five seconds, fifth level nodes could have a built ineffective delay time of sixty seconds, sixth level nodes could have abuilt in effective delay time of forty-five seconds, seventh level nodescould have a built in effective delay time of thirty seconds, and eighthlevel nodes could have a built in effective delay time of fifteenseconds.

The delays may take advantage of the fact that transmission of thepackets forming the content data from one node to another may take lesstime than the actual playing of such packets. This may allow foressentially simultaneous playing of the content data throughout all thelevels of the distribution network. The delays may also allow nodes tohandle reconnection and reconfiguration events without any significantloss of content data.

In another example (which example is intended to be illustrative and notrestrictive), the system may not endeavor to have buffers closer to theserver contain more data than buffers of nodes that are further away.Instead, every node may have a buffer that can hold, for example,approximately two minutes worth of A/V content. The system may endeavorto fill every node's buffer as rapidly as possible, regardless of thenode's distance from the server, in order to give each node the maximumamount of time possible to deal with network reconfiguration and uptreenode failure events.

Of note, nodes may receive a “current play time index” when they connectto the server. This value may be used to keep all nodes at approximatelythe same point in the stream—to have all nodes playing approximately thesame moment of video at the same time—by telling them, essentially,begin playing A/V content at this time index. The play time index maybe, for example, approximately two minutes behind “real time”—allowingfor nodes to buffer locally up to two minutes of content (the presentinvention may permit drift between nodes within the buffer (e.g., twominute buffer) or the present invention may reduce or eliminate thisdrift to keep all nodes playing closer to “lock step”).

Referring now to what will hereinafter be called a “Virtual Tree” (or“VTree”) embodiment, FIG. 32 shows a server of a distribution networkconfigured to include a number of “virtual” nodes (such virtual nodesmay provide “multi-node” or “super-node” capability). More particularly,in this example (which example is intended to be illustrative and notrestrictive), the server is a single computer running software whichprovides functionality for seven distinct nodes (as a result, thissingle computer includes 4 leaves (Nodes V3-V6) to which downtree usernodes (not shown) may connect). Of note, root node N may be thought ofas “real”—because there is one real machine running the software (all ofthe other nodes (i.e., V1, V2, V3, V4, V5 and V6) may be thought of as“virtual”, since they are all running on node N's hardware.

In another example (which example is intended to be illustrative and notrestrictive), the server is a single computer running software whichprovides functionality for four distinct nodes. More particularly, inthe example in FIG. 33, the VTree of the server is configured with: (i)one 3^(rd) level leaf (Node V3) to which downtree user nodes (not shown)may connect; (ii) a 2^(nd) level leaf (Node VI) to which one downtreeuser node (not shown) may connect (and to which Node V3 is connected);and (iii) another 2^(nd) level leaf (Node V2) to which downtree usernodes (not shown) may connect. Again, root node N may be thought of as“real”—because there is one real machine running the software (all ofthe other nodes (i.e., V1, V2, and V₃) may be thought of as “virtual”,since they are all running on node N's hardware.

In one example (which example is intended to be illustrative and notrestrictive), the computer (e.g., server) may run multiple instances ofsoftware, each of which instances provides the functionality for one ofthe virtual nodes (e.g., by using a portion of memory as a “port”).

In another example (which example is intended to be illustrative and notrestrictive), the computer (e.g., server) may run a single instance ofsoftware to provide the functionality for a plurality (e.g., all) of thevirtual nodes on the server (e.g., by using a portion of memory as a“port”).

Of course, even though the configurations shown in these FIGS. 32 and 33are binary tree configurations having branch factors of 2, any otherdesired branch factors may be utilized.

Further, any desired combinations or permutations of the configurationsshown in these FIGS. 32 and 33 may be utilized.

In another embodiment, such virtual nodes may be implemented by one ormore user computers.

In another embodiment a distribution network for the distribution ofdata between a first computer system and a second computer system isprovided, which distribution network comprises: a first software programrunning on the first computer system for enabling the first computersystem to perform as a node in the network; and a second softwareprogram running on the second computer system for enabling the secondcomputer system to perform as a plurality of virtual nodes in thenetwork.

In one example, the second computer system is a server.

In another example, the second computer system is a user computer.

In another example, the first software program and the second softwareprogram utilize the same source code.

In another example, the first software program and the second softwareprogram utilize different source code.

In another embodiment a distribution network for the distribution ofdata between a first computer system and a second computer system isprovided, which distribution network comprises: a first software programrunning on the first computer system for enabling the first computersystem to perform as a node in the network; and a plurality of instancesof a second software program running on the second computer system forenabling the second computer system to perform as a plurality of virtualnodes in the network.

In one example, the second computer system is a server.

In another example, the second computer system is a user computer.

In another example, the first software program and the second softwareprogram utilize the same source code.

In another example, the first software program and the second softwareprogram utilize different source code.

In another embodiment, data flowing between one or more nodes in thenetwork (e.g. between a server node and a user node and/or between oneuser node and another user node) may be encrypted (e.g., using a publickey/private key mechanism). In one example (which example is intended tobe illustrative and not restrictive), the encryption may be applied toonly a checksum portion of the data flow. In another example (whichexample is intended to be illustrative and not restrictive), theencryption may be applied to all of one or more messages.

Of note, the present invention may provide a mechanism to help ensurethat hackers: (1) can not construct nodes which pose as the server andissue destructive commands, such as network shutdown messages; and (2)can not intercept the broadcast data stream and replace that stream withsome other stream (e.g., replacing a network feed of CNN withpornography). In one example (which example is intended to beillustrative and not restrictive), the present invention may operate byhaving nodes receive from the server, as part of the meta data sent by aserver to all connection requesting nodes, a public key. This public keymay then used by (e.g., every node in the system) to verify that: (1)the content of every data packet; and (2) the content of all non-datapackets sent in the “secure message format” were produced by the serverand have not been altered in any way prior to their arrival at thisnode, regardless of the number of nodes that have “rebroadcast” thepacket. In other words, nodes rebroadcast data packets and securepackets to their children completely unaltered from the form in whichthey were received from their parent. In one specific example (whichexample is intended to be illustrative and not restrictive), to reduceoverhead, the root server encodes (using its private key) only thechecksum information associated with each data packet and secure packet.Because every node in the network can independently verify what thechecksum of a packet should be and also decrypt the encrypted checksumattached to that message by the server, every node can independentlyverify that a packet has been received unaltered from the root server.Packets that have been altered in any way may be rejected as invalid andignored by the system.

In another embodiment, a node (e.g., a server node) may store some orall data flowing to/from the node (e.g., information relating to acertain number of prior connect instructions, information relating toprior network topology). In one example (which example is intended to beillustrative and not restrictive), the stored data may be “replayed”(e.g., such as to aid in network reconfiguration). In another example(which example is intended to be illustrative and not restrictive), suchstored data may be associated with certain time information and suchreplay may utilize the stored time information for timing purposes.

In another embodiment, a node (e.g., a server node) may store some orall information regarding connection requests and its response toconnection requests. In one example (which example is intended to beillustrative and not restrictive), the stored data may be “replayed”(e.g., such as to aid in modeling the network configuration). In anotherexample (which example is intended to be illustrative and notrestrictive), such stored data may be associated with a system time andsuch replay may utilize the stored time information to model the networkconfiguration at a particular time. In addition, such time informationmay be utilized with propagated network data so that the node (e.g., aserver node) can more accurately model the network configuration.

In another embodiment, the following process may be employed when a nodeenters the network. More particularly, when the server adds a node X tothe system (gives it a connection path to node Y) the server will addnode X to its network topology model as a child of node Y. In otherwords, the server will assume that the connection will take placenormally with no errors. The reason why doing so may be critical to thefunctioning of the system in this embodiment is that if the serverfailed to account for the fact that node X is now (probably) a child ofnode Y, using the “keep the tree balanced” approach embodied in theUniversal Connection Address Routine, all new nodes connecting to thesystem would be assigned as children of node Y up until the point wherea propagate up arrives indicating that node X was successfully added tothe tree. If the tree is large and node Y is many levels removed fromthe server it could be some time (e.g., a minute or more, in very largetrees several minutes) before confirmation arrives that node X trulyconnected to node Y as its child.

Now, in addition to simply placing node X into the server's NTM (NetworkTopology Model) and being done with the matter, in this embodiment thesystem must account for the fact that it may take a number of propagateNTM/up cycles for the true status of node X to be reported back to theserver. Thus, for some number of propagate cycles (or some amount oftime) the server may compare the newly propagated (updated) NTM it isreceiving from its children to the list of “recently added nodes”. If arecently added node is not in the propagated NTM it will be re-added tothe NTM as a child of node Y. At some point node X will no longer beconsidered “recently added” and the server will cease adding node X backinto its NTM. In other words, the server will assume that, for whateverreason, node X never successfully connected to the network.

In another embodiment, the following process may be employed when a nodegracefully exits the system. More particularly, when a node (node X)leaves the network by performing a graceful exit (e.g., the user selects“exit” or clicks the “x” or issues some other command to close theapplication) the node will send signals to its parent and child nodes(if any) immediately prior to actually shutting down. Upon receipt ofsuch a “depart” message, the parent of the departing node (node P) willmodify its internal NTM (Network Topology Model) to a configuration thatcorresponds to the predicted shape of the network after the departingnode exits. In this embodiment, node P will assume that its NTM isaccurate and that the entire cascade of reconfiguration events initiatedby the departure of node X will happen normally. As such, node P willnow expect the former green child of node X (node XG—if such a childexists) to connect—essentially taking node X's place in the network.

At this point, node P's NTM represents a prediction of the (anticipated)state of the network rather than the actual reported configuration. Inorder to indicate that node P does not (yet) have a physical connectionto node XG, node P will mark node XG as “soft” in its NTM—meaning nodeXG is expected to take up this position in the network but has not yetphysically done so. Node P will report this “predicted” NTM (along withnode XG's status as a soft node) up during its propagate NTM/Up cycles,until node P physically accepts a child connection in node XG's“reserved” spot and receives an actual report of the shape of thedowntree NTM from that child, via propagate NTM/ups.

Of note, the above actions may be taken in order to have the propagatedNTM's reflect, as accurately as possible, the topology of the network.

Of further note, because of the distributed nature of a networkaccording to the present invention, a complete and accurate picture ofthe current shape of the network at any instance in time can never beguaranteed. In fact, though the root server has the “widest” view of thenetwork, without the heuristics described herein, that view would be the“most dated” of any node in the network. Thus, heuristics such as thosejust described may be vital to producing NTM's that are as close tocomplete and accurate as possible (e.g., so that the UniversalConnection Address Routine can position incoming nodes so as to keep thedistribution tree as nearly balanced as possible).

In another embodiment, some or all of the data flowing in the networkmay be associated with a particular data type (e.g., audiovisual data,closed caption data, network control data, file data). Further, dataflowing in the network may be stored for user use at a later time (e.g.,data of the type “file” may contain program guide data and may be storedfor use by a user (or the client program) at a later time).

More particularly, while the present invention may be utilized tobroadcast audio/video content “live” (which traditional peer-to-peerfile sharing systems such as BitTorrent, KaZaA, etc. are poorly suitedfor), various embodiments of the present invention may have the abilityto distribute various kinds of content in addition to audio visualmaterial. For example (which example is intended to be illustrative andnot restrictive), the system of the present invention may routinelytransmit commands between nodes and data concerning the topology of thenetwork. Further, the system of the present invention may be capable ofstreaming Closed Captioning text information to accompany A/V material.Further still, the system of the present invention may capable oftransmitting files “in the background” while A/V content is beingbroadcast. Further, the system of the present invention may be capableof distributing any form of digital data, regardless of type or size.

The following embodiments will now describe a number of additionalexample algorithms which may be utilized in whole or in part toimplement the present invention:

In one embodiment a process for docking a connection requesting usernode with a distribution network is provided, said process including thefollowing steps:

(a) having an instructing node receive a connection request from saidconnection requesting user node;

(b) forming an instructing node topology database indicating, at a pointin time:

-   -   (i) which, if any, user nodes are docked with said instructing        node as child nodes; which, if any, user nodes are docked with        each of said child nodes as grandchild nodes of said instructing        node; which, if any, user nodes are docked with each of said        grandchild nodes as great-grandchild nodes of said server node;        and so on; and    -   (ii) said docked user nodes respective bandwidth capacities;

(c) selecting from a group of nodes including the instructing node andsaid docked user nodes a recommended parent node for said connectionrequesting user node, wherein said recommended parent node has apparentavailable capacity to transmit content data to said connectionrequesting user node and is at least as close (i.e., in terms of networktopology) to said instructing node as any other docked user node havingapparent available capacity to transmit content data to said connectionrequesting user node (of note, placement may also or alternativelydepend, as described elsewhere in the present application, in whole orin part on whether the connection requesting node is repeat-capable ornot (i.e., whether it can support children)); and

(d) providing a connection address list to said connection requestinguser node, said connection address list listing each node in saidinstructing node's topology database from said recommended parent nodeback to said instructing node.

In one example, the process may further comprise the following steps:

(e) having said connection requesting user node go to (or attempt to goto) the node at the top of said connection address list;

(f) having said connection requesting user node determine whether thenode at the top of said connection address list is part of thedistribution network;

(g) if the node at top of said connection address list is not part ofthe distribution network, deleting such node from said connectionaddress list and repeating steps (e) and (f) with respect to the nextnode at the top of said connection address list;

(h) if the node at the top of said connection address list is part ofsaid distribution network, having said connection requesting user nodedock with said node at the top of said connection address list.

In another example, step (d) may further comprise the following step:

(i) if said instructing node is not a server node, including in saidconnection address list a list of nodes cascadingly connected with eachother from the instructing node back to said server node.

In another example, the process may further comprise the followingsteps:

(e) having said connection requesting user node go to (or attempt to goto) the node at the top of said connection address list;

(f) having said connection requesting user node determine whether thenode at the top of said connection address list is part of thedistribution network;

(g) if the node at the top of said connection address list is not partof the distribution network, deleting such node from said connectionaddress list and repeating steps (e) and (f) with respect to the nextnode at the top of said connection address list;

(h) if the node at the top of said connection address list is part ofsaid distribution network, determining whether said node at the top ofsaid connection address list has available capacity to transmit contentdata to said connection requesting user node; and

(i) if the node at the top of said connection address list is part ofsaid distribution network and has available capacity to transmit contentdata to said connection requesting user node, having said connectionrequesting user node dock with the node at the top of said connectionaddress list.

In another example, the process may further comprise the followingsteps:

(j) if the node at the top of connection address list is part of saiddistribution network and said node at the top of said connection addresslist does not have available capacity to transmit content data to saidconnection requesting user node, repeating steps (a)-(d), with said nodeat the top of connection address list being said instructing node and anew connection address list being the product of steps (a)-(d).

In another example, the process may further comprise the steps ofcounting the times that step (j) is performed and, when step (j) isperformed a predetermined number of times, having said connectionrequesting user node repeat steps (a)-(d) with said primary server beingthe instructing node.

In another embodiment a process for docking a connection requesting usernode with a distribution network is provided, said process including thefollowing steps:

(a) having an instructing node receive a connection request from saidconnection requesting user node;

(b) forming an instructing node topology database indicating, at a pointin time:

-   -   (i) which, if any, user nodes are docked with said instructing        node as child nodes; which, if any, user nodes are docked with        each of said child nodes as grandchild nodes of said instructing        node; which, if any, user nodes are docked with each of said        grandchild nodes as great-grandchild nodes of said server node;        and so on; and    -   (ii) said docked user nodes' respective bandwidth capacities;

(c) assigning utility ratings to each of the docked user nodes, saidutility ratings being a function of at least the bandwidth capacity ofthe docked user node and the elapsed time that the docked user node hasbeen docked with the distribution network;

(d) selecting from a group of nodes including the instructing node andsaid docked user nodes a recommended parent node for said connectionrequesting user node, wherein said recommended parent node has apparentavailable capacity to transmit content data to said connectionrequesting user node and is at least as close (i.e., in terms of networktopology) to said instructing node as any other docked user node havingapparent available capacity to transmit content data to said connectionrequesting user node, and when the closest (i.e., in terms of networktopology) docked user node with apparent available capacity to transmitcontent data to said connection requesting user node is equidistant(i.e., in terms of network topology) to said instructing node with atleast one other docked user node with apparent available capacity totransmit content data to said connection requesting user node, saidrecommended parent node is the docked user node having the highestutility rating among such equidistant (i.e., in terms of networktopology) docked user nodes with apparent available capacity; and

(e) providing a connection address list to said connection requestinguser node, said connection address list listing each node in saidinstructing node's topology database from said recommended parent nodeback to said instructing node and, if said instructing node is not aprimary server node, back to said primary server node.

In another embodiment a process for docking a connection requesting usernode with a distribution network is provided, said process including thefollowing steps:

(a) having an instructing node receive a connection request from saidconnection requesting user node;

(b) forming an instructing node topology database indicating, at a pointin time:

-   -   (i) which, if any, user nodes are docked with said instructing        node as child nodes; which, if any, user nodes are docked with        each of said child nodes as grandchild nodes of said instructing        node; which, if any, user nodes are docked with each of said        grandchild nodes as great-grandchild nodes of said instructing        node; and so on; and    -   (ii) said docked user nodes' respective bandwidth capacities,        including a designation of whether said respective docked user        node's bandwidth capacity is below a predetermined threshold        (e.g., said respective docked user node is a low-bandwidth node)        or at least said predetermined threshold (e.g., said respective        docked user node is a high-bandwidth node);

(c) forming a primary recommended parent node list (“PRPL”) comprised ofthe instructing node (if it has available capacity to transmit contentdata to said connection requesting user node) plus those docked usernodes having apparent available capacity to transmit content data tosaid connection requesting user node, with said instructing node beingplaced first on the PRPL (if it is on the PRPL) and said docked usernodes having apparent available capacity to transmit content date tosaid connection requesting user node being ranked with those dockednodes which are closer (i.e., in terms of network topology) to theinstructing node being ranked higher than those docked nodes which arefurther away (i.e., in terms of network topology) and with equidistant(i.e., in terms of network topology) docked user nodes being ranked suchthat those docked nodes which have the higher utility ratings beingranked higher than docked nodes having lower utility ratings;

(d) forming a secondary recommended parent node list (“SRPL”) comprisedof the instructing node (if it has no available capacity to transmitcontent data to said connection requesting user node but does have atleast one low-bandwidth node docked directly to it) plus said dockeduser nodes which (i) are high-bandwidth nodes with no available capacityto transmit content data to said connection requesting user node and(ii) have at least one low-bandwidth node docked directly to it, withsaid instructing node being placed first on the SRPL (if it is on theSRPL) and said docked user nodes on the SRPL being ranked with thosedocked nodes which are closer (i.e., in terms of network topology) tothe instructing node being ranked higher than those docked nodes whichare further away (i.e., in terms of network topology) and withequidistant (i.e., in terms of network topology) docked user nodes beingranked such that those docked nodes which have the higher utilityratings being ranked higher than docked nodes having lower utilityratings;

(e) determining whether the connection requesting user node is alow-bandwidth node;

(f) if the connection requesting user node is a low-bandwidth node:

-   -   (i) selecting the highest ranked node on the PRPL as a        recommended parent node; and    -   (ii) providing a connection address list to said connection        requesting user node, said connection address list listing each        node in said instructing node's topology database from said        recommended parent node back to said instructing node and, if        said instructing node is not a primary server node, back to said        primary server node; and

(g) if the connection requesting user node is a high-bandwidth node:

-   -   (i) selecting the highest ranked node on the PRPL as a        recommended parent node;    -   (ii) selecting the highest ranked node on the SRPL as an        alternate recommended parent node;    -   (iii) determining whether the alternate recommended parent node        is closer (i.e., in terms of network topology) to the server        node than the recommended parent node;    -   (iv) if the alternate recommended parent node is not closer        (i.e., in terms of network topology) to the server node than the        recommended parent node, providing a connection address list to        said connection requesting user node, said connection address        list listing each node in said instructing node's topology        database from said recommended parent node back to said        instructing node and, if said instructing node is not the        primary server node, back to said primary server node;    -   (v) if the alternate recommended parent node is closer (i.e., in        terms of network topology) to the server node than the        recommended parent node, (1) forcing the disconnection of a        low-bandwidth node from the alternate recommended parent node        and (2) providing a connection address list to said connection        requesting user node, said connection address list listing each        node in said instructing node's topology database from said        alternate recommended parent node back to said instructing node        and, if said instructing node is not the primary server node,        back to said primary server node. In one example, step (f) (ii)        may include the following steps:

(1) adding said connection requesting user node to the topology databaseas a child of the recommended parent node; and

(2) if said recommended parent node would have no apparent availablecapacity to transmit content data to an additional node with saidconnection requesting user node docked with it, deleting the recommendedparent node from the PRPL and adding it to the SRPL.

In another example, step (g) (iv) may include the following steps:

(1) adding said connection requesting user node to the topology databaseas a child of the recommended parent node;

(2) if said recommended parent node would have no apparent availablecapacity to transmit content data to an additional node with saidconnection requesting user node docked with it, deleting the recommendedparent node from the PRPL; and

(3) if said recommended parent node is deleted from the PRPL but has atleast one low-bandwidth node docked directly to it, adding therecommended parent node to the SRPL. In another example, step (g) (v)may include the following steps:

(3) adding said connection requesting user node to the topology databaseas a child of the alternate recommended parent node; and

(4) if said alternate recommended parent node would have no apparentavailable capacity to transmit content data to an additional node withsaid connection requesting user node docked with it, deleting thealternate recommended parent node from the SRPL.

In another example, the process may further comprise the followingsteps:

(h) having said connection requesting user node go to (or attempt to goto) the node at the top of said connection address list;

(i) having said connection requesting user node determine whether thenode at the top of said connection address list is part of thedistribution network;

(j) if the node at top of connection address list is not part of thedistribution network, deleting such node from connection address listand repeating steps (h) and (i) with respect to the next node at the topof connection address list; and

(k) if the node at top of connection address list is part of saiddistribution network, having said connection requesting user node dockwith said node at the top of connection address list. In anotherexample, the process may further comprise the following steps:

(h) having said connection requesting user node go to (or attempt to goto) the node at the top of connection address list;

(i) having said connection requesting user node determine whether thenode at the top of said connection address list is part of thedistribution network;

(j) if the node at top of connection address list is not part of thedistribution network, deleting such node from connection address listand repeating steps (h) and (i) with respect to the next node at the topof connection address list;

(k) if the node at the top of connection address list is part of saiddistribution network, determining whether said node at the top ofconnection address list has available capacity to transmit content datato said connection requesting user node; and

(l) if the node at the top of said connection address list is part ofsaid distribution network and has available capacity to transmit contentdata to said connection requesting user node, having said connectionrequesting user node dock with the node at the top of said connectionaddress list.

In another example, the process may further comprise the followingsteps:

(m) if the node at the top of said connection address list is part ofsaid distribution network and the node at the top of said connectionaddress list does not have available capacity to transmit content datato said connection requesting user node, repeating steps (a)-(g), withthe node at the top of said connection address list being saidinstructing node and a new connection address list being the product ofsteps (a)-(g).

In another example, the process may further comprise the steps ofcounting the times that step (m) is performed and, when step (m) isperformed a predetermined number of times, having said connectionrequesting user node repeat steps (a)-(g) with said primary server beingthe instructing node.

In another embodiment a process for docking a connection requesting usernode with a distribution network is provided, said process including thefollowing steps:

(a) having an instructing node receive a connection request from saidconnection requesting user node;

(b) determining whether said connection requesting user node's bandwidthcapacity is below a predetermined threshold (e.g., said connectionrequesting user node is a low-bandwidth node) or at least saidpredetermined threshold (e.g., said connection requesting user node is ahigh-bandwidth node);

(c) forming an instructing node topology database indicating, at a pointin time:

-   -   (i) which, if any, user nodes are docked with said instructing        node as child nodes; which, if any, user nodes are docked with        each of said child nodes as grandchild nodes of said instructing        node; which, if any, user nodes are docked with each of said        grandchild nodes as great-grandchild nodes of said server node;        and so on; and    -   (ii) said docked user nodes' respective bandwidth capacities;

(d) if said connection requesting user node is a high-bandwidth usernode, selecting from a group of nodes including the instructing node andsaid docked user nodes a recommended parent node for said connectionrequesting user node, wherein said recommended parent node has apparentavailable capacity to transmit content data to said connectionrequesting user node and is at least as close (i.e., in terms of networktopology) to said instructing node as any other docked user node havingapparent available capacity to transmit content data to said connectionrequesting user node;

(e) if said connection requesting user node is a low-bandwidth usernode, selecting from a group of nodes including the instructing node andsaid docked user nodes a recommended parent node for said connectionrequesting user node, wherein said recommended parent node has apparentavailable capacity to transmit content data to said connectionrequesting user node and is at least as far (i.e., in terms of networktopology) from said instructing node as any other docked user nodehaving apparent available capacity to transmit content data to saidconnection requesting user node; and

(f) providing a connection address list to said connection requestinguser node, said connection address list listing each node in saidinstructing node's topology database from said recommended parent nodeback to said instructing node.

In one example, step (f) may further comprise the following step: (i) ifsaid instructing node is not a server node, including in said connectionaddress list a list of nodes cascadingly connected with each other fromthe instructing node back to said server node.

In another embodiment a process for connecting a connection requestinguser node to a computer information distribution network having aprimary server node and user nodes docked therewith in a cascadedrelationship is provided, said process further comprising the followingsteps:

(a) providing said connection requesting user node with a connectionaddress list which sets forth a list of user nodes docked in series witheach other back to said primary server;

(b) having said connection requesting user node go to (or attempt to goto) the node at top of said connection address list;

(c) having said connection requesting user node determine whether thenode at the top of said connection address list is part of thedistribution network;

(d) if the node at the top of said connection address list is not partof the distribution network, deleting such node from said connectionaddress list and repeating steps (b) and (c) with respect to the nextnode at the top of connection address list; and

(e) if the node at the top of said connection address list is part ofsaid distribution network, having said connection requesting user nodedock with the node at the top of said connection address list.

In another embodiment a process for connecting a connection requestinguser node to a computer information distribution network having aprimary server node and user nodes docked therewith in a cascadedrelationship is provided, said process further comprising the followingsteps:

(a) providing said connection requesting user node with a connectionaddress list which sets forth a list of user nodes docked in series witheach other back to said primary server;

(b) having said connection requesting user node go to (or attempt to goto) the node at the top of said connection address list;

(c) having said connection requesting user node determine whether thenode at the top of said connection address list is part of thedistribution network;

(d) if the node at the top of said connection address list is not partof the distribution network, deleting such node from connection addresslist and repeating steps (b) and (c) with respect to the next node atthe top of said connection address list;

(e) if the node at the top of said connection address list is part ofsaid distribution network, determining whether the node at the top ofsaid connection address list has available capacity to transmit contentdata to said connection requesting user node; and

(f) if the node at the top of said connection address list is part ofsaid distribution network and has available capacity to transmit contentdata to said connection requesting user node, having said connectionrequesting user node dock with the node at the top of said connectionaddress list.

In another embodiment relating to a computer information distributionnetwork comprising a primary server node and user nodes docked therewithin a cascaded relationship, wherein each user node may have no more thana predetermined maximum number of child nodes docked with it, a processfor reconfiguring the network in the event of a user node's departuretherefrom is provided, said process including the following steps:

(a) providing information at a point in time to a node in thedistribution network as follows:

-   -   (i) the node's propagation rating if it is a user node having a        parent node which is a user node, wherein a propagation rating        is one of a predetermined number of grades ranging from highest        to second highest to third highest and so on, with the number of        grades being equal to said predetermined maximum number;    -   (ii) an ancestor list setting forth the node's ancestor nodes'        addresses (if it has any ancestor nodes) back to the primary        server node, with the node's parent node being atop the ancestor        list;    -   (iii) a sibling list of the node's sibling nodes' addresses (if        it has any sibling nodes) and their respective propagation        ratings (of note, in another example (which example is intended        to be illustrative and not restrictive), nodes may not have data        about their sibling (i.e., nodes do not know who their sibling        is); instead, the mechanism used to get a red node to connect to        its green sibling may be for the parent of those two nodes (or a        proxy for that parent) to send the red child: (1) a connection        path with that red child's green sibling at the top of the path;        and (2) a command to “priority join” to that green child—when        the green child node accepts the incoming “priority join”        connection request from its former red sibling, the green node        will kick its own red child (if such a child exists) instructing        that red child to join as a child of its own green sibling        (these actions will cause a chain reaction of reconfigurations        which will cascade until the edge of the tree is reached)); and    -   (iv) a child list of the node's child nodes' addresses (if it        has any child nodes) and their respective propagation ratings;

(b) having a first node send a propagation signal to each former childnode of a departed node, wherein said first node is an ancestor of saidformer child node of said departed node;

(c) with respect to each child node receiving the propagation signalwhich did not have the highest propagation rating prior to its receivingthe propagation signal (hereinafter referred to as a “red node”), uponits receiving the propagation signal:

-   -   (i) setting the propagation rating of the red node to the next        higher grade above the propagation rating of that red node        before it received the propagation signal;    -   (ii) having the red node undock from its parent node (if it was        docked with its parent node before it received the propagation        signal); and    -   (iii) having the red node dock with its sibling node which had        the highest propagation rating prior to the red node's receiving        the propagation signal;

(d) with respect to each child node receiving the propagation signalwhich had the highest propagation rating prior to its receiving apropagation signal (hereinafter referred to as a “green node”), upon itsreceiving the propagation signal:

-   -   (i) setting the propagation rating of that green node to the        lowest grade;    -   (ii) having the green node retransmit the propagation signal to        its child nodes (if it has any); and    -   (iii) determining whether the green node is docked with the node        from which the green node received the propagation signal and if        it is, having the green node remain docked with said node from        which the green node received the propagation signal, and if it        is not, having the green node dock with said node from which the        green node received the propagation signal; and

(e) repeating steps (c) and (d) with respect to each user node whichreceives a retransmitted propagation signal.

In another embodiment relating to a computer information distributionnetwork comprising a primary server node and user nodes docked therewithin a cascaded relationship, wherein each user node may have no more thana predetermined maximum number of child nodes docked with it, a processfor reconfiguring the network in the event of a user node's departuretherefrom is provided, said process including the following steps:

(a) providing information at a point in time to a node in thedistribution network as follows:

-   -   (i) the node's propagation rating if it is a user node having a        parent node which is a user node, wherein a propagation rating        is one of a predetermined number of grades ranging from highest        to second highest to third highest and so on, with the number of        grades being equal to said predetermined maximum number;    -   (ii) an ancestor list setting forth the node's ancestor nodes'        addresses (if it has any ancestor nodes) back to the primary        server node, with the node's parent node being atop the ancestor        list;    -   (iii) a sibling list of the node's sibling nodes' addresses (if        it has any sibling nodes) and their respective propagation        ratings; and    -   (iv) a child list of the node's child nodes' addresses (if it        has any child nodes) and their respective propagation ratings;

(b) having a first node send a propagation signal to each former childnode of a departed node, wherein said first node is an ancestor of saidformer child node of said departed node;

(c) with respect to each child node receiving the propagation signalwhich did not have the highest propagation rating prior to its receivingthe propagation signal (hereinafter referred to as a “red node”), uponits receiving the propagation signal:

-   -   (i) setting the propagation rating of the red node to the next        higher grade above the propagation rating of that red node        before it received the propagation signal;    -   (ii) having the red node undock from its parent node (if it was        docked with its parent node before it received the propagation        signal);    -   (iii) devising a first connection address list comprising the        address of the red node's sibling node which had the had the        highest propagation rating prior to the red node's receiving the        propagation signal followed by the red node's ancestor list;    -   (iv) having said red node go to (or attempt to go to) the node        at the top of said first connection address list;    -   (v) having said red node determine whether the node at the top        of said first connection address list is part of the        distribution network;    -   (vi) if the node at the top of said first connection address        list is not part of the distribution network, deleting such node        from said first connection address list and repeating        steps (c) (iv) and (c) (v) with respect to the next node at the        top of said first connection address list;    -   (vii) if the node at the top of said first connection address        list is part of said distribution network, determining whether        the node at the top of said first connection address list has        available capacity to transmit content data to said red node;        and    -   (viii) if the node at the top of said first connection address        list is part of said distribution network and has available        capacity to transmit content data to said red node, having said        red node dock with the node at the top of said first connection        address list (with regard to these steps (vii) and (viii), in        another example (which example is intended to be illustrative        and not restrictive), when a red node connects to a green node        as part of a network reconfiguration event, it does not matter        whether there is “available capacity” or not for the green node        to accept its incoming red sibling—the green node has no choice        but to accept the node (these actions are facilitated in this        example by the red node issuing a “priority join” to the green        node; if the green node does not have “available capacity” it        has to kick its own red child to make room for the incoming        green node)); (d) with respect to each child node receiving the        propagation signal which had the highest propagation rating        prior to its receiving a propagation signal (hereinafter        referred to as a “green node”), upon its receiving the        propagation signal:    -   (i) setting the propagation rating of that green node to the        lowest grade;    -   (ii) having the green node retransmit the propagation signal to        its child nodes (if it has any);    -   (iii) determining whether the green node is docked with the node        from which the green node received the propagation signal and if        it is, having the green node remain docked with said node from        which the green node received the propagation signal, and if it        is not, devising a second connection address list starting with        said node from which the green node received the propagation        signal and followed by that portion of said green node's        ancestor list extending back to the primary server from said        node from which the green node received the propagation signal;    -   (iv) having said green node go to (or attempt to go to) the node        at the top of said second connection address list;    -   (v) having said green node determine whether the node at the top        of said second connection address list is part of the        distribution network;    -   (vi) if the node at the top of said second connection address        list is not part of the distribution network, deleting such node        from said second connection address list and repeating        steps (d) (iv) and (d) (v) with respect to the next node at the        top of said second connection address list;    -   (vii) if the node at the top of said second connection address        list is part of said distribution network, determining whether        said node at the top of said second connection address list has        available capacity to transmit content data to said green node;        and    -   (viii) if the node at the top of said second connection address        list is part of said distribution network and has available        capacity to transmit content data to said green node, having        said green node dock with the node at the top of said second        connection address list; and

(e) repeating steps (c) and (d) with respect to each user node whichreceives a retransmitted propagation signal.

In one example, step (c) (iii) may include the following additionalstep: (1) waiting a predetermined period of time so as to allow the rednode's sibling with the highest propagation rating prior to the rednode's receipt of the propagation signal (hereinafter the “green node”)to retransmit the propagation signal to the green node's child nodes (ifany).

In another embodiment relating to a computer information distributionnetwork comprising an instructing node having a first user node dockedwith said instructing node to receive content data therefrom and asecond user node docked with said first user node to receive contentdata therefrom, a process for handling a purported communicationinterruption between said first user node and said second user node isprovided, said process including the following steps:

(a) having said instructing node receive a first complaint about saidfirst user node from said second user node;

(b) if the second user node is the only user node docked with said firstuser node at a point in time, if said instructing node receives anothercomplaint about the first user node from another user node within apredetermined period of time from when said instructing node receivedsaid first complaint or if said instructing node experiences acommunication problem between it and said first user node during saidpredetermined period of time: (i) disconnecting said first user nodefrom said instructing node; and

(c) if said instructing node has not experienced a communication problembetween it and said first user node during said predetermined period oftime and if a plurality of user nodes are docked with said first usernode at said point in time and said instructing node has not receivedanother complaint about said first user node from a user node other thansaid second user node within said predetermined period of time: (i)disconnecting said second user node from said first user node.

In one example, step (b) may include the following step: (ii) sending asignal to the user nodes docked with said first user node indicating thedeparture of said first user node from said network.

In another example, each user node may have no more than a predeterminedmaximum number of child nodes docked with it, and wherein step (b) mayinclude the following steps:

(ii) providing information at said point in time to each of said seconduser node, the other user nodes which had been docked with said firstuser node (if any) and at least one of any user nodes cascadinglyconnected in the distribution network under said first user node priorto said first user node's being disconnected from said instructing node(if any) as follows:

-   -   (1) the node's propagation rating, wherein a propagation rating        is one of a predetermined number of grades ranging from highest        to second highest to third highest and so on, with the number of        grades being equal to said predetermined maximum number;    -   (2) an ancestor list setting forth the node's ancestor nodes'        addresses (if it has any ancestor nodes) back to the instructing        node, with the node's parent node being atop the ancestor list;    -   (3) a sibling list of the node's sibling nodes' addresses (if it        has any sibling nodes) and their respective propagation ratings;        and    -   (4) a child list of the node's child nodes' addresses (if it has        any child nodes) and their respective propagation ratings;

(iii) having said instructing node send a propagation signal to each ofsaid second user node and the other user nodes which had been dockedwith said first user node (if any);

(iv) with respect to each user node receiving the propagation signalwhich did not have the highest propagation rating prior to its receivingthe propagation signal (hereinafter referred to as a “red node”), uponits receiving the propagation signal:

-   -   (1) setting the propagation rating of the red node to the next        higher grade above the propagation rating of that red node        before it received the propagation signal;    -   (2) having the red node undock from its parent node (if it was        docked with its parent node before it received the propagation        signal); and    -   (3) having the red node dock with its sibling node which had the        highest propagation rating prior to the red node's receiving the        propagation signal;

(v) with respect to each user node receiving the propagation signalwhich had the highest propagation rating prior to its receiving apropagation signal (hereinafter referred to as a “green node”), upon itsreceiving the propagation signal:

-   -   (1) setting the propagation rating of that green node to the        lowest grade;    -   (2) having the green node retransmit the propagation signal to        its child nodes (if it has any); and    -   (3) determining whether the green node is docked with the node        from which the green node received the propagation signal and if        it is, having the green node remain docked with said node from        which the green node received the propagation signal, and if it        is not, having the green node dock with said node from which the        green node received the propagation signal; and

(vi) repeating steps (iv) and (v) with respect to each user node whichreceives a retransmitted propagation signal.

In another embodiment a distribution network for the distribution ofcontent data from a server node to user nodes, wherein said user nodesare connected to said server and each other in cascaded relationship isprovided, wherein:

(a) at least one of said user nodes is a repeater node connecteddirectly to said server node, wherein said repeater node retransmitscontent data received by it to a user node docked to it for purpose ofreceiving content data from said repeater node (hereinafter referred toas a “child node”); and

(b) wherein each repeater node has the ability to provide to a user nodewhich is attempting to dock with said repeater node connection addressinstructions.

In one example, each repeater node may include a descendant databaseindicating:

(i) which child nodes, if any, at a point in time, are docked with it soas to receive content data from said repeater node, and

(ii) which user nodes, if any, at said point in time, are purportedlydocked with each of said child nodes.

In another example, the connection address instructions may refer saiduser node which is attempting to dock with said repeater node to a nodein said descendant database.

In another example, each user node may include an ancestor databaseindicating to which node said user node is docked so that said user nodemay receive content data therefrom (hereinafter referred to as a “parentnode”), and to which node, if any, at said point in time, said parentnode is docked so that it may receive content data therefrom.

In another example, if said parent node of said user node departs fromsaid distribution network, said user node may contact another node onits ancestor database.

In another example, each child node of a repeater node may include asibling database indicating which user nodes, if any, are also childnodes of said repeater node.

In another embodiment a distribution network for the distribution ofcontent data from a server node to user nodes is provided, wherein nlevels of user nodes are cascadingly connected to said server node,wherein n is a number greater than one, wherein each user node includesa delay which causes the playing of content data by such node to bedelayed a period of time (hereinafter “delay time”) from a point intime, and wherein delays in higher level nodes create greater delaytimes than do delays in lower level nodes.

In another embodiment a distribution network for the distribution ofcontent data from a server node to user nodes is provided, wherein nlevels of user nodes are cascadingly connected to said server node,wherein n is a number greater than one, wherein each user node includesa delay which causes the playing of content data by such node to bedelayed a period of time (hereinafter “delay time”) from a point intime, wherein x is a number from and including 2 to and including n, andwherein delays in (x−1) level nodes create greater delay times than dodelays in x level nodes.

In one example, said point in time is an event experienced approximatelysimultaneously by substantially all user nodes.

In another example, said point in time is when said node receivescontent data.

While a number of embodiments and examples of the present invention havebeen described, it is understood that these embodiments and examples areillustrative only, and not restrictive, and that many modifications maybecome apparent to those of ordinary skill in the art. For example, anydesired branch factor may be used (see, e.g., FIG. 34A showing a branchfactor of 1 (i.e., each parent node may have only one child node); FIG.34B showing a branch factor of 2 (i.e., each parent node may have one ortwo children nodes); and FIG. 34C showing a branch factor of 3 (i.e.,each parent node may have one, two or three children nodes)). Of course,other branch factors (e.g., 4, 5, 6, etc) may be used and, as discussedabove, the distribution network may be a hybrid network utilizingsubtrees having different branch factors). Further still, a modifiedUtility Rating may be determined as follows: Utility Rating=Time (ofconnection)×Bandwidth Rating. Further still, a node ID may be basedupon: (a) an IP address (external/internal/DHCP); (b) a URL; and/or (c)a Port. Further still, the root server may propagate “its” time uponassignment of a connection and the user node may get a “delta” (i.e.,difference) from its clock to use (in the event of a reset the user nodemay re-acquire the time from the server (or from another time-providingsource)). Further still, the various time intervals discussed herein maybe predetermined time intervals (e.g., 0.5 sec., 1 sec, 1 min.) and/orthe time intervals may be based upon some varying criteria (e.g., flowof data in the network, number of nodes in the network, number of levelsin the network, position of a given node in the network). Further still,partial propagation of data (e.g., ancestor data and/or descendent data)from one or more nodes may be permitted. Further still (as discussedabove), one or more of the steps described herein may be omitted (andthe various steps which are performed may not necessarily need to becarried out in the order described herein (which description wasintended to represent a number of examples, and not be restrictive)).Further still, the root server and each of the user nodes may utilizeessentially identical software for carrying out the networkconfiguration, reconfiguration and data transfer operations describedherein or the root server may have dedicated server software while theuser nodes have different, dedicated user node software. Further still,the entire distribution network (e.g., the root server and all of theuser nodes) may have the same branch factor (e.g., a branch factor of 2)or the user nodes may have a first branch factor (e.g., a branch factorof 2) and the root server may have a second branch factor (e.g., theroot server may be capable of acting as a parent to more user nodes than2). Further still, heuristics may be employed to drive networkconfiguration, reconfiguration and/or data flow (e.g., based uponhistoric network configuration, reconfiguration and/or data flow).

1. A super-node formed from a plurality of nodes in binary tree topologynetwork, the super-node comprising: a multitasking computing systemhaving a memory; a first node running the computing system, the firstnode being docked downtree of and with a parent node running on a firstseparate computing system, the first node having a first socket adaptedto be docked uptree of a first child node and a second socket adapted tobe docked uptree of a second child node; a second node running on thecomputing system, the second node being virtually docked downtree of andwith the first node over the first socket, the second node having athird socket adapted to be docked uptree of a third child node and afourth socket adapted to be docked uptree of a fourth child node; and atleast one selected from the group of the second socket, the third socketor the fourth socket being configured to be docked uptree of and with achild node running on a second separate computing system.
 2. Thesuper-node claimed in claim 1, wherein the second socket, the thirdsocket and the fourth socket are configured to be docked uptree of andwith respective children nodes not running on the multitasking computingsystem.
 3. The super-node claimed in claim 1, further comprising a thirdnode running on the computing system, the third node being virtuallydocked downtree of and with the first node over the second socket, thethird node having a fifth socket adapted to be docked uptree of a fifthchild node and a sixth socket adapted to be docked uptree of a sixthchild node.
 4. The super-node claimed in claim 3, wherein the thirdsocket, the fourth socket, the fifth socket and the sixth socket areconfigured to be docked uptree of and with respective children nodes notrunning on the multitasking computing system, thus proving a super-nodecapable of having four children in a binary tree topology network.
 5. Asuper-node formed from a plurality of nodes in a binary tree topologynetwork, the super-node comprising: a multitasking computing systemhaving a memory; a plurality of nodes running the computing system, eachof the plurality of nodes being adapted to be docked downtree of andwith another node, and being adapted to be docked uptree of and with twoother nodes, the plurality of nodes including a first node; the firstnode being docked downtree of and with a parent node running on a firstseparate computing system; each node of the plurality of nodes exceptthe first node being docked downtree of and with another one of theplurality of nodes; thereby forming a super-node having more than twosockets available for connection with nodes not running on themultitasking computing system.
 6. The super-node claimed in claim 5,wherein each of the plurality of nodes running the computing system areseparate instances of the same software.
 7. A method of forming avirtual tree in a binary tree topology network, the method comprisingthe steps of: instantiating a first node on a first computer, the firstnode being adapted to dock downtree of and with one node, and adapted todock uptree of and with two nodes; docking the first node downtree ofand with a parent node running on a first separate computer system;instantiating a second node on the first computer, the second node beingadapted to dock downtree of and with one node, and adapted to dockuptree of and with two nodes; and docking the second node downtree ofand with the first node, thereby forming a virtual tree capable ofdocking uptree of and with at least three nodes in a binary treetopology network, which three nodes are not running on the firstcomputer.
 8. The method of claim 7, further comprising the steps of:instantiating a third node on the first computer, the third node beingadapted to dock downtree of and with one node, and adapted to dockuptree of and with two nodes; and docking the third node downtree of andwith the first node, thereby forming a virtual tree capable of dockinguptree of and with at least four nodes in a binary tree topologynetwork, which four nodes are not running on the first computer.
 9. Themethod of claim 8, further comprising the steps of: instantiating afourth node on the first computer, the fourth node being adapted to dockdowntree of and with one node, and adapted to dock uptree of and withtwo nodes; and docking the fourth node downtree of and with the secondnode, instantiating a fifth node on the first computer, the fifth nodebeing adapted to dock downtree of and with one node, and adapted to dockuptree of and with two nodes; and docking the fifth node downtree of andwith the third node, thereby forming a virtual tree capable of dockinguptree of and with a plurality of nodes not running on the firstcomputer.
 10. A method for securing a downtree data transmission in abinary tree topology network, the network including a plurality ofnodes, including a root node and at least one leaf node, operativelynetworked together to provide a downtree communications path for data,each of the plurality of nodes except the root node being dockeddowntree of a parent node, the parent node being one of the plurality ofnodes, and each of the plurality of nodes adapted to be docked uptree ofa first child node and a second child node, each of the at least oneleaf nodes having none of the plurality of nodes docked downtree of andtherewith, the method comprising the steps of: the root node maintaininga first key; providing to each of the plurality of nodes except the rootnode a second key corresponding to the first key maintained by the rootnode; encrypting at least a portion of the downtree data transmissionusing the first key; at least one of the plurality of nodes decryptingthe portion of the downtree data transmission; and verifying thedecrypted portion of the downtree data transmission, and rejecting thedowntree data transmission if the verification fails.
 11. A methodclaimed in claim 10, wherein the first key is a private keycorresponding to the root node, and wherein the second key is a publickey corresponding to the root node.
 12. A method claimed in claim 10,wherein the downtree data transmission has a checksum as part thereof,and wherein the at least a portion of the downtree data transmissionthat is encrypted is the checksum.